Difference between revisions of "NC 100/150/200 IO Specification"

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−
 
 
This update to NCIOSPEC.TXT covers the differences between the NC100 hardware
 
This update to NCIOSPEC.TXT covers the differences between the NC100 hardware
−
(documented in the original NCIOSPEC.TXT below) and the NC200 hardware.
+
(documented in the original NCIOSPEC.TXT below) and the NC150/NC200 hardware.
  
 
This information was discovered mainly by Russell Marks during development of his
 
This information was discovered mainly by Russell Marks during development of his
Line 7: Line 6:
 
during development of my NC200 emulation for M.E.S.S.
 
during development of my NC200 emulation for M.E.S.S.
  
−
This update does not cover the NC150. I do not have details of any differences
+
This update does not cover the NC150. I do not have details of any differences between this and the NC100 at this time.
−
between this and the NC100 at this time.
+
  
 
When I have information on this system, it will be documented here.
 
When I have information on this system, it will be documented here.
Line 15: Line 13:
 
of I/O read/writes.
 
of I/O read/writes.
  
−
- The NC200 does not have a TC8521 Real Time Clock, instead it
+
* The NC200 does not have a TC8521 Real Time Clock, instead it has a MC146818 Real Time Clock. The MC146818 is no longer produced now, but is part of many PC designs.
−
has a MC146818 Real Time Clock. The MC146818 is no longer produced now,
+
−
but is part of many PC designs.
+
  
−
- The NC200 has a NEC765 compatible floppy disc controller. The disc
+
* The NC200 has a [[NEC765]] compatible floppy disc controller. The disc interface was designed by Ranger Computers.
−
interface was designed by Ranger Computers.
+
  
 
The ports listed in this section are different or have additional
 
The ports listed in this section are different or have additional
Line 27: Line 22:
  
  
−
The NC100 clock speed is 4.606Mhz, at this time it is unknown if the NC200
+
* The NC100 clock speed is 4.606MHz, at this time it is unknown if the NC200 has a different clock speed.
−
has a different clock speed.
+
  
−
Address                Comment                R/W
+
* The NC100 on/off button generates an NMI.
−
=======                =======                ===
+
* The NC200 on/off button generates a maskable interrupt.
  
−
00 Display Memory start W
+
Keyboard NC100:
−
20 Memory card wait state W
+
−
A0 Card Battery status R
+
−
60 Interrupt Request Mask W
+
−
70 on/off control W
+
−
80 Printer Status R
+
−
90 IRQ Status R
+
−
B0-B9 Key data in R
+
−
D0-D1 MC146818 Real Time Clock R/W
+
−
E0                 NEC765 Status          R
+
−
E1 NEC765 Data R/W
+
  
 +
B0:
 +
bit 0: Shift (Left)
 +
bit 1: Shift (Right)
 +
bit 2: unused
 +
bit 3: Cursor Left (Red)
 +
bit 4: Return
 +
bit 5: unused
 +
bit 6: unused
 +
bit 7: unused
  
−
Address = 00                                    Write only
+
B1:
−
start address of display memory
+
bit 0: Function (Yellow)
−
----------------------------------------------------------
+
bit 1: Control
 +
bit 2: Stop
 +
bit 3: Space
 +
bit 4: unused
 +
bit 5: unused
 +
bit 6: 5
 +
bit 7: unused
 +
 +
B2:
 +
bit 0: Caps Lock
 +
bit 1: Symbol
 +
bit 2: 1
 +
bit 3: Tab
 +
bit 4: unused
 +
bit 5: unused
 +
bit 6: unused
 +
bit 7: unused
  
−
        bit 7          A15
+
B3:
−
        bit 6          A14
+
bit 0: 3
−
        bit 5          A13
+
bit 1: 2
−
        bits 4-0        Not Used
+
bit 2: Q
 +
bit 3: W
 +
bit 4: E
 +
bit 5: unused
 +
bit 6: S
 +
bit 7: D
  
−
Address = 20                                    Write only
+
B4:
−
Memory card wait state control
+
bit 0: 4
−
----------------------------------------------------------
+
bit 1: unused
−
+
bit 2: Z
−
        bit 7: memory card wait state control:  1 for wait states, 0 for no wait
+
bit 3: X
−
bit 2: ??
+
bit 4: A
−
bit 1: ??
+
  bit 5: unused
−
bit 0: NEC765 Terminal Count input (1=TC active, 0=TC inactive)
+
bit 6: R
 +
bit 7: F
 +
 +
B5:
 +
bit 0: ??
 +
bit 1: ??
 +
bit 2: B
 +
bit 3: V
 +
bit 4: T
 +
bit 5: Y
 +
bit 6: G
 +
bit 7: C
  
−
Address = 70
+
B6:
−
on/off control
+
bit 0: 6
−
----------------------------------------------------------------
+
bit 1: Cursor Down (Blue)
 +
bit 2: Del
 +
bit 3: Cursor Right (Green)
 +
bit 4: \
 +
bit 5: /
 +
bit 6: H
 +
bit 7: N
  
−
bit 2: Backlight: 1=off, 0=on
+
B7:
−
bit 1: ??
+
bit 0: =
−
bit 0: on/off control: 1 = on, 0 = off
+
bit 1: 7
 +
bit 2: ~
 +
bit 3: Up
 +
bit 4: Menu
 +
bit 5: U
 +
bit 6: M
 +
bit 7: K
  
−
Address = A0
+
B8:
−
Card battery status
+
bit 0: 8
−
----------------------------------------------------------------
+
bit 1: -
 +
bit 2: )
 +
bit 3: (
 +
bit 4: "
 +
bit 5: I
 +
bit 6: J
 +
bit 7: ,
  
−
bit 7: memory card present 0 = yes, 1 = no
+
B9:
−
bit 6: memory card write protected 1 = yes, 0 = no
+
bit 0: 0
−
bit 5: lithium battery 0 if >= 2.7 volts
+
bit 1: 9
−
bit 4: input voltage = 1, if >= to 4 volts
+
bit 2: Del
−
bit 3: ** unknown use **
+
bit 3: P
−
bit 2: alkaline batteries. 0 if >=3.2 volts
+
bit 4: :
−
bit 1: ** unknown use **
+
bit 5: L
−
bit 0: battery power: if 1: batteries are too low for disk usage, if 0: batteries ok for disc usage
+
bit 6: O
 +
bit 7: .
  
−
Address = B0 - B9                                Read only
 
−
Keyboard data
 
−
-----------------------------------------------------------
 
  
−
        B0..B9          each key of the 64 on the keyboard
 
−
                        will set a bit in one of these bytes
 
−
                        while pressed.
 
  
−
Russell Marks confirms that reading B9 does not clear the key scan interrupt
 
−
like it does on the NC100. The interrupt must be explicitly cleared!
 
  
−
Address = 60                                    Write only
+
Address                 Comment                R/W
−
Interrupt request mask
+
=======                =======                ===
−
----------------------------------------------------------
+
−
 
+
−
        bit 7: ** unknown use **
+
−
bit 6: ** unknown use ** (Real Time Clock Alarm?)
+
−
bit 5: NEC765 FDC
+
−
        bit 4: Power off interrupt
+
−
bit 3          Key scan
+
−
        bit 2          TC8251 Serial Interrupt (Tx Ready OR Rx Ready)
+
−
        bit 1          ** unknown use ** (not checked by OS - not used?)
+
−
        bit 0          ACK from parallel interface
+
−
 
+
−
Address = 80
+
−
Printer status
+
−
----------------------------------------------------------
+
−
bit 7..1: * unknown use *
+
−
bit 0: printer busy status
+
−
1 = busy
+
−
 
+
−
Address = 90                                    Read/Write
+
−
IRQ status
+
−
-----------------------------------------------------------
+
−
 
+
−
        bit 7: ** unknown use **
+
−
bit 6: ** unknown use ** (Real Time Clock Alarm?)
+
−
bit 5: NEC765 FDC
+
−
        bit 4: Power off interrupt
+
−
bit 3          Key scan
+
−
        bit 2          TC8251 Serial Interrupt (Tx Ready OR Rx Ready)
+
−
        bit 1          ** unknown use ** (not checked by OS - not used?)
+
−
        bit 0          ACK from parallel interface
+
 
   
 
   
 +
00 Display Memory start W
 +
20 Memory card wait state W
 +
A0 Card Battery status R
 +
60 Interrupt Request Mask W
 +
70 on/off control W
 +
80 Printer Status R
 +
90 IRQ Status R
 +
B0-B9 Key data in R
 +
D0-D1 MC146818 Real Time Clock R/W
 +
E0                 NEC765 Status          R
 +
E1 NEC765 Data R/W
  
−
Address = D0/D1                                   
 
−
MC146818 Real Time Clock
 
−
----------------------------------------------------------
 
−
Consult MC146818 datasheet.
 
−
 
−
 
−
Address = E0/E1                                   
 
−
NEC765 floppy disc controller
 
−
----------------------------------------------------------
 
−
Consult NEC765 datasheet.
 
−
 
−
Read:
 
−
 
−
E0 = Status, E1 = data
 
−
 
−
Write:
 
−
 
−
E0 = not used, E1 = data
 
−
 
−
 
−
---
 
−
Kev Thacker
 
−
 
−
 
−
 
−
 
−
Original NCIOSPEC.TXT follows:
 
−
 
−
The following notes describe the low level operation of the Amstrad Notepad
 
−
computers. They are intended for third party developers who want to program
 
−
the Notepad in machine code.
 
−
 
−
As always, I will try to help out if anyone has questions about this but I
 
−
cannot give an absolute guarantee to be able to provide support on the low
 
−
level operation of the machine.
 
−
 
−
It is our intention that these firmware routines and system variables should
 
−
be maintained in future issues of the software but we cannot give an absolute
 
−
guarantee about this.
 
−
 
−
Cliff Lawson                            CIS: 75300,1517
 
−
Notepad project manager                email: cliffl@amstrad.com
 
−
Amstrad Plc                                    amstrad@cix.compulink.co.uk
 
−
169 Kings Road                          Phone: (+44) 277 208341
 
−
Brentwood                              Fax: (+44) 277 208065
 
−
Essex
 
−
CM14 4EF
 
−
ENGLAND
 
−
 
−
 
−
        I/O Specification for Amstrad NC100
 
−
        <<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>
 
−
 
−
All numbers are in hexadecimal unless suffixed with a "b" for binary or
 
−
"d" for decimal. (Address line numbers A19, A18, etc are in decimal).
 
−
 
−
                        SUMMARY
 
−
                        =======
 
−
 
−
Address                Comment                R/W
 
−
=======                =======                ===
 
−
 
−
E0-FF                  Not Used                -
 
−
D0-DF                  RTC (TC8521)            R/W
 
−
C0-C1                  UART (uPD71051)        R/W
 
−
B0-B9                  Key data in            R
 
−
A0                      Card Status etc.        R
 
−
90                      IRQ request status      R/W
 
−
80-8F                  Not Used
 
−
70                      Power on/off control    W
 
−
60                      IRQ Mask                W
 
−
50-53                  Speaker frequency      W
 
−
40                      Parallel port data      W
 
−
30                      Baud rate etc.          W
 
−
20                      Card wiat control      W
 
−
10-13                  Memory management      R/W
 
−
00                      Display memory start    W
 
−
 
−
 
−
                        In Detail
 
−
                        =========
 
  
 
Address = 00                                    Write only
 
Address = 00                                    Write only
 
start address of display memory
 
start address of display memory
−
----------------------------------------------------------
 
  
−
        bit 7          A15
 
−
        bit 6          A14
 
−
        bit 5          A13
 
−
        bit 4          A12
 
−
        bits 3-0        Not Used
 
−
 
−
On reset this is set to 0.
 
−
 
−
The display memory for the 8 line NC computers consists of a block of 4096
 
−
bytes where the first byte defines the state of the pixels in the top left
 
−
hand corner of the screen. A 1 bit set means the pixel is set to black. The
 
−
first byte controls the first 8 dots with bit 7 controlling the bit on the
 
−
left. The next 59 bytes complete the first raster line of 480 dots. The bytes
 
−
which define the second raster line start at byte 64 to make the hardware
 
−
simpler so bytes 60, 61, 62 and 63 are wasted. There are then another 64 bytes
 
−
(with the last 4 unused) which defines the second raster line and so on
 
−
straight down the screen. That is (all numbers decimal):
 
−
 
−
                byte00  byte01  byte02      byte60  byte61    byte63
 
−
Bit Number      76543210 76543210 76543210 .. 76543210 76543210.. 76543210
 
−
 
−
Pixel Number    01234567 89012345 67890123 .. 23456789  wasted .. wasted
 
−
(read bottom    00000000 00111111 11112222    77777777
 
−
to top decimal) 00000000 00000000 00000000    44444444
 
−
 
−
....and so on for subsequent lines. (Second line = bytes 64..127 etc.)
 
−
 
−
 
−
Address = 10..13                              Read/Write
 
−
Memory management control
 
−
--------------------------------------------------------
 
−
 
−
        10              controls 0000-3FFF
 
−
        11              controls 4000-7FFF
 
−
        12              controls 8000-BFFF
 
−
        13              controls C000-FFFF
 
−
 
−
On reset all are set to 0.
 
−
 
−
For each address the byte written has the following meaning:
 
−
 
−
        bit 7          together they select ROM, internal RAM, card RAM
 
−
        bit 6                  00b = ROM
 
−
                                01b = internal RAM
 
−
                                10b = card RAM
 
−
 
−
        bits 5-0        determine address lines 19 to 14.
 
−
 
−
Therefore, 00 is the first 16K of ROM, 01 is the second 16K, etc.
 
−
          40 is the first 16K of internal RAM, 41=second 16K, etc.
 
−
          80 is the first 16K of card RAM, 81=second 16K, etc.
 
−
 
−
So, for example, if you want to switch the third 16K of internal RAM so the
 
−
processor sees it at 4000-7FFF you would output the value 42 to I/O address
 
−
11.  42 has bits 7,6 = 01b and bits 5-0 are 00010b which is the third 16K of
 
−
internal RAM.
 
  
 +
bit 7          A15
 +
bit 6          A14
 +
bit 5          A13
 +
bits 4-0        Not Used
  
 
Address = 20                                    Write only
 
Address = 20                                    Write only
 
Memory card wait state control
 
Memory card wait state control
−
----------------------------------------------------------
+
−
 
+
bit 7: memory card wait state control:  1 for wait states, 0 for no wait
−
        bit 7 = 1 for wait states, 0 for no wait
+
bit 0: NEC765 Terminal Count input (1=TC active, 0=TC inactive)
−
 
+
−
On reset this is set to 1. The bit should be set if the card RAM/ROM is
+
−
200nS or slower.
+
−
 
+
  
 
Address = 30                                    Write only
 
Address = 30                                    Write only
−
Baud rate etc.
+
Floppy motor control
−
----------------------------------------------------------
+
 +
bit 3: Floppy motor: 1=off, 0=on
  
−
        bit 7    select card register 1=common, 0=attribute
+
Address = 70
−
        bit 6    parallel interface Strobe signal
+
on/off control
−
        bit 5    Not Used
+
−
        bit 4    uPD4711 line driver, 1=off, 0=on
+
−
        bit 3    UART clock and reset, 1=off, 0=on
+
  
−
        bits 2-0  set the baud rate as follows
 
  
−
                000 = 150
+
bit 2: Backlight: 1=off, 0=on
−
                001 = 300
+
bit 0: on/off control: 1 = on, 0 = off
−
                010 = 600
+
−
                011 = 1200
+
−
                100 = 2400
+
−
                101 = 4800
+
−
                110 = 9600
+
−
                111 = 19200
+
  
−
On reset all data is set to 1.
 
  
−
If programming the UART directly ensure that TxD clock is operating x16.
+
Address = 80
 +
centronics status
  
−
Address = 40                                    Write only
+
bit 0: busy state
−
Parallel interface data
+
−
----------------------------------------------------------
+
  
−
The byte written here is latched into the parallel port output register. To
+
Address = A0
−
print it you must then take the Strobe signal (I/O address 30 bit 6) low and
+
Card battery status
−
then high again. If the printer sends ACK this may generate an IRQ if the mask
+
−
bit is set in I/O address 60 - IRQ mask.
+
  
−
Address = 50..53                                Write only
 
−
Sound channels period control
 
−
----------------------------------------------------------
 
  
−
        50      channel A period low
+
bit 7: memory card present 0 = yes, 1 = no
−
        51      channel A period high
+
bit 6: memory card write protected 1 = yes, 0 = no
 +
bit 5: lithium battery 0 if >= 2.7 volts
 +
bit 4: input voltage = 1, if >= to 4 volts
 +
bit 3: ** unknown use **
 +
bit 2: alkaline batteries. 0 if >=3.2 volts
 +
bit 1: ** unknown use **
 +
bit 0: battery power: if 1: batteries are too low for disk usage, if 0: batteries ok for disc usage
  
−
        52      channel B period low
+
Address = B0 - B9                                Read only
−
        53      channel B period high
+
Keyboard data
  
−
On reset all data is set to FF. The top bit in the high byte (51 and 53)
 
−
switches the resepective sound generator on or off - 1=off, 0=on.
 
  
−
The frequency generated is determined as:
+
B0..B9          each key of the 64 on the keyboard
−
 
+
                        will set a bit in one of these bytes
−
        Frequency = 1,000,000d
+
                        while pressed.
−
                    ----------
+
−
                    data * 2 * 1.6276
+
−
 
+
−
So if the data word programmed into 50 and 51 was 7800 (ie 50=0, 51=78) then
+
−
the frequency generated would be:
+
−
 
+
−
    freq = 1,000,000          =  1,000,000          = 1,000,000  = 10Hz
+
−
            ---------              ---------            ---------
+
−
            7800h * 2 * 1.6276    30720 * 2 * 1.6276      99,999.7
+
  
 +
Russell Marks confirms that reading B9 does not clear the key scan interrupt
 +
like it does on the NC100. The interrupt must be explicitly cleared!
  
 
Address = 60                                    Write only
 
Address = 60                                    Write only
 
Interrupt request mask
 
Interrupt request mask
−
----------------------------------------------------------
 
  
−
        bits 7-4        Not Used
 
−
        bit 3          Key Scan interrupt (every 10mS)
 
−
        bit 2          ACK from parallel interface
 
−
        bit 1          Tx Ready from UART
 
−
        bit 0          Rx Ready from UART
 
  
−
On reset all bits are 0. For each bit, 1=allow that interrupt source to
+
bit 7: ** unknown use **
−
produce IRQs. 0 = interrupt source is masked.
+
bit 6: ** unknown use ** (Real Time Clock Alarm?)
 +
bit 5: NEC765 FDC
 +
bit 4: Power off interrupt
 +
bit 3          Key scan
 +
bit 2          TC8251 Serial Interrupt (Tx Ready OR Rx Ready)
 +
bit 1          ** unknown use ** (not checked by OS - not used?)
 +
bit 0           ACK from parallel interface
  
−
Address = 70                                    Write only
+
Address = 80
−
Power off control
+
Printer status
−
----------------------------------------------------------
+
  
−
        bits 7-1       Not Used
+
bit 7..1: * unknown use *
−
        bit 0           1 = no effect, 0 = power off
+
bit 0: printer busy status
−
 
+
1 = busy
−
On reset this is set to 1.
+
  
 
Address = 90                                    Read/Write
 
Address = 90                                    Read/Write
 
IRQ status
 
IRQ status
−
-----------------------------------------------------------
 
  
−
        bits 7-4        Not Used
 
−
        bit 3          Key scan
 
−
        bit 2          ACK from parallel interface
 
−
        bit 1          Tx Ready interrupt
 
−
        bit 0          Rx Ready interrupt
 
  
−
When an interrupt occurs this port should be read to determine the source of
+
bit 7: ** unknown use **
−
the interrupt. The bit will be set to 0 to identify the interrupting device.
+
bit 6: ** unknown use ** (Real Time Clock Alarm?)
−
The interrupt can then be cleared by writing 0 to that bit.
+
bit 5: NEC765 FDC
 +
bit 4: Power off interrupt
 +
bit 3          Key scan
 +
bit 2          TC8251 Serial Interrupt (Tx Ready OR Rx Ready)
 +
bit 1          ** unknown use ** (not checked by OS - not used?)
 +
bit 0          ACK from parallel interface
 +
  
−
Address = A0                                    Read only
+
Address = D0/D1                                   
−
Memory card/battery status
+
MC146818 Real Time Clock
−
----------------------------------------------------------
+
  
−
        bit 7          Memory card present 0 = yes, 1 = no
+
Consult MC146818 datasheet.
−
        bit 6          Card write protected 1 = yes, 0 = no
+
  
−
        bit 5          Input voltage = 1 if >= to 4 Volts
 
−
        bit 4          Mem card battery. 0 = battery is low
 
−
        bit 3          Alkaline batteries. 0 if >= 3.2 Volts
 
−
        bit 2          Lithium battery. 0 if >= 2.7 Volts
 
  
−
        bit 1          Parallel interface BUSY (0 if busy)
+
Address = E0/E1                                   
−
        bit 0          Parallel interface ACK  (1 if ACK)
+
NEC765 floppy disc controller
  
 +
Consult NEC765 datasheet.
  
−
Address = B0 - B9                                Read only
+
Read:
−
Keyboard data
+
−
-----------------------------------------------------------
+
  
−
        B0..B9          each key of the 64 on the keyboard
+
E0 = Status,
−
                        will set a bit in one of these bytes
+
E1 = data
−
                        while pressed.
+
  
−
The gate array scans the keyboard every 10mS and then generates an
+
Write:
−
interrupt. The program should then read these 10 I/O locations to
+
−
determine which key(s) is pushed. When I/O address B9 is read the
+
−
key scan interrupt is cleared automatically and the next scan cycle
+
−
will start from B0.
+
−
 
+
−
Address = C0                                      Read/Write
+
−
UART control/data
+
−
------------------------------------------------------------
+
−
 
+
−
        C0              UART data register
+
−
        C1              UART status/control register
+
−
 
+
−
The UART is the NEC uPD71051. Programmers are advised to study the data
+
−
sheet for that chip for more information. The Serial interface requires
+
−
that the uPD4711 line driver chip be truned on by writing a 0 to bit 4 of
+
−
I/O address 30. While turned on power consumption increases so this should
+
−
only be done when necessary.
+
−
 
+
−
Address = D0                                    Read/Write
+
−
Real Time Clock chip (TM8521)
+
−
----------------------------------------------------------
+
−
 
+
−
        D0..DC          Data
+
−
        DD              Control register
+
−
        DE              Control register        (Write only)
+
−
        DF              Control register        (Write only)
+
−
 
+
−
See data sheet of chip for more information.
+
−
 
+
−
=================================================================
+
−
 
+
−
                NC100 operating system firmware
+
−
                <<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>
+
−
 
+
−
notes for external program writers
+
−
==================================
+
−
 
+
−
To get external programs executed on the Notepad you could either POKE
+
−
them into memory in BBC BASIC (or even use its built-in Z80 assembler)
+
−
and then CALL the entry point. However, this does have the drawback of
+
−
needing to transfer the code back to the machine each time it crashes
+
−
(as it inevitably will).
+
−
 
+
−
The simplest way to develop for the Notepad is to get a PCMCIA drive
+
−
for your PC and write a binary image direct to the card using that. If
+
−
this isn't possible then small programs (up to 16K) can be developed by
+
−
transferring the binary card image into the Notepad using Xmodem from
+
−
the PC. The use the "Make program card" feature in the File, transfer
+
−
menu to write that file onto a newly formatted PCMCIA RAM card.
+
−
 
+
−
In either case, to run the resultant code, you just press Function-X
+
−
(eXecute) and the first 16K page of the RAM card will be switched to
+
−
the Z80 memory map at C000..FFFF. A Check is made that location C200
+
−
holds the ASCII text "NC100PRG" and also that locations C210..C212
+
−
contains a long jump to C220. All being well, the Z80 starts executing
+
−
code at C210 so that, once you have control, you can take over
+
−
completely if you wish (driving all hardware functions directly). Most
+
−
people will probably want to cooperate with the in built firmware as it
+
−
provides most of the routines that one would require anyway.
+
−
 
+
−
 
+
−
The ASCII text "NC100PRG" must appear at C200h
+
−
program origin is C210h
+
−
program MUST start with jp C220h
+
−
the program name is at C213h, max 12 characters, zero terminated
+
−
 
+
−
                          org C200h
+
−
                          db "NC100PRG"
+
−
                          org c210h
+
−
                          jp start
+
−
                          db "PROGRAM NAME",0
+
−
                          org C220h
+
−
                  start
+
−
 
+
−
available workspace A000h to A3FFh (shared with other programs)
+
−
also A800h to AFFFh (this is overwritten if selectfile is called)
+
−
the program MUST handle yellow events :-
+
−
  either exit when Stop is pressed
+
−
  or check for yellow event with kmgetyellow and return if carry set
+
−
 
+
−
Serious developers may be interested in contacting Ranger Computers Ltd
+
−
on (+44) 604 589200 as they can produce a device that looks like RAM to
+
−
a PC but ends in a PCMCIA header plug that connects directly to the
+
−
Notepad's card slot and the "PC RAM" appears as card RAM to the Notepad.
+
−
 
+
−
 
+
−
The following sequence is a working(!) piece of code written for the
+
−
AVMACZ80 assembler on a PC, which, when assmembled produces a binary
+
−
file that can be programmed onto a PCMCIA card and executed. The
+
−
program just reads keys and prints them back until "Q" is pressed.
+
−
 
+
−
Notice that exit from the program is just by a RET back to the
+
−
operating system that called it:
+
−
 
+
−
;VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV
+
−
 
+
−
        include "nc100jmp.inc"          ;The list of firmware routine
+
−
                                        ;addresses given later in this
+
−
                                        ;file
+
−
 
+
−
 
+
−
        DEFSEG  Fred, CLASS=CODE, START=0
+
−
 
+
−
        SEG    Fred    ;Seg will be linked to RUNSAT C000h
+
−
 
+
−
        jp      start  ;put a jump at the start in case this code is
+
−
                        ;ever programmed into a ROM page where the entry
+
−
                        ;will almost certainly be made at the more
+
−
                        ;normal C000.
+
−
        ds      509    ;waste first 512 bytes of card to start at C200
+
−
;
+
−
; following 16 bytes are Arnor's header for card at C200
+
−
;
+
−
        db      "NC100PRG",0,0,0,0,0,3,0,1
+
−
;
+
−
; then card program must start with this long jump at C210
+
−
;
+
−
        jp      start                  ;this is at C210h
+
−
        db      "CLIFFS PROG",0,0      ;0's pad to C220h
+
−
 
+
−
start:
+
−
        call    kmreadchar
+
−
        ld      a,c
+
−
        cp      "q"
+
−
        jr      z,finish
+
−
        call    txtoutput
+
−
        jr      start
+
−
 
+
−
finish:
+
−
        ret
+
−
 
+
−
        end
+
−
 
+
−
;^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
−
; code is assembled with:
+
−
;      AVMACZ80 TEST.ASM
+
−
;which produces a .OBJ file which is then linked to produce a .HEX file
+
−
;with the command
+
−
;      AVLINK @TEST.LNK
+
−
;where TEST.LNK contains:
+
−
;      TEST.HEX=TEST.OBJ -RUNSAT(Fred, 0C000h)
+
−
;finally the Intel .HEX file is converted to .BIN using a HEX2BIN converter
+
−
;The .BIN file is either written to the PCMCIA card using a PC based
+
−
;card drive or it can be Xmodemed across to the Notepad and written to
+
−
;the card using "Make program card". Finally, Function-X executes it.
+
−
 
+
−
In other assemblers you may not have "segments" and must use a direct
+
−
ORG to locate code at C000 but watch out for the resultant .HEX file
+
−
being padded out with 48K of "0"s from 0000 to BFFF!!
+
−
 
+
−
 
+
−
Alphabetic list of routine entry points
+
−
=======================================
+
−
 
+
−
To use any one of these routines just load the registers as described in
+
−
the following and then call the relevant address. Although the running of the
+
−
routine may involve a different ROM bank being switched in, this mechanism
+
−
is invisble to the caller. So, for example, to print a capital A one might use:
+
−
 
+
−
txtoutput      EQU    B833
+
−
                LD      A,"A"
+
−
                CALL    txtoutput
+
−
 
+
−
col1            equ B818h
+
−
col1text        equ B81Bh
+
−
diskservice    equ BA5Eh
+
−
editbuf        equ B800h
+
−
fclose          equ B890h
+
−
fdatestamp      equ B8C9h
+
−
ferase          equ B893h
+
−
fgetattr        equ B8CFh
+
−
finblock        equ B896h
+
−
finchar        equ B899h
+
−
findfirst      equ B89Ch
+
−
findnext        equ B89Fh
+
−
fnoisy          equ B917h
+
−
fopenin        equ B8A2h
+
−
fopenout        equ B8A5h
+
−
fopenup        equ B8A8h
+
−
foutblock      equ B8ABh
+
−
foutchar        equ B8AEh
+
−
fquiet          equ B91Ah
+
−
frename        equ B8B1h
+
−
fseek          equ B8B4h
+
−
fsetattr        equ B8CCh
+
−
fsize          equ B8B7h
+
−
fsizehandle    equ B8BAh
+
−
ftell          equ B8BDh
+
−
ftesteof        equ B8C0h
+
−
heapaddress    equ B87Eh
+
−
heapalloc      equ B881h
+
−
heapfree        equ B884h
+
−
heaplock        equ B887h
+
−
heapmaxfree    equ B88Ah
+
−
heaprealloc    equ B88Dh
+
−
kmcharreturn    equ B803h
+
−
kmgetyellow    equ B8D2h
+
−
kmreadkbd      equ B806h
+
−
kmreadchar      equ B9B3h
+
−
kmsetexpand    equ B809h
+
−
kmsettickcount  equ B80Ch
+
−
kmsetyellow    equ B8D5h
+
−
kmwaitkbd      equ B80Fh
+
−
lapcat_receive  equ B8D8h
+
−
lapcat_send    equ B8DBh
+
−
mcprintchar    equ B851h
+
−
mcreadyprinter  equ B854h
+
−
mcsetprinter    equ B857h
+
−
padgetticker    equ B872h
+
−
padgettime      equ B875h
+
−
padgetversion  equ B8DEh
+
−
padinitprinter  equ BA4Fh
+
−
padinitserial  equ B85Ah
+
−
padinserial    equ B85Dh
+
−
padoutparallel  equ B860h
+
−
padoutserial    equ B863h
+
−
padreadyparallel equ B866h
+
−
padreadyserial  equ B869h
+
−
padresetserial  equ B86Ch
+
−
padserialwaiting equ B86Fh
+
−
padsetalarm    equ B878h
+
−
padsettime      equ B87Bh
+
−
pagemodeon      equ BA49h
+
−
pagemodeoff    equ BA4Ch
+
−
readbuf        equ B812h
+
−
selectfile      equ B8C3h
+
−
setdta          equ B8C6h
+
−
testescape      equ B815h
+
−
textout        equ B81Eh
+
−
textoutcount    equ B821h
+
−
txtboldoff      equ B83Fh
+
−
txtboldon      equ B842h
+
−
txtclearwindow  equ B824h
+
−
txtcuroff      equ B827h
+
−
txtcuron        equ B82Ah
+
−
txtgetcursor    equ B82Dh
+
−
txtgetwindow    equ B830h
+
−
txtinverseoff  equ B845h
+
−
txtinverseon    equ B848h
+
−
txtoutput      equ B833h
+
−
txtsetcursor    equ B836h
+
−
txtsetwindow    equ B839h
+
−
txtunderlineoff equ B84Bh
+
−
txtunderlineon  equ B84Eh
+
−
txtwrchar      equ B83Ch
+
−
 
+
−
 
+
−
Notepad memory map
+
−
==================
+
−
                          16K code/data sections always mapped to C000h
+
−
ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿        ÚÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÂÄÄÄÄÂÄÄÄÄÂÄÄÄÄÄÂÄÄÄÄÄÄ¿
+
−
³  video RAM  ³        ³Protext ³Dictionary³Con-³Calc³Addr³Diary³ BBC  ³
+
−
³---------------³        ³        ³  data    ³trol³    ³book³    ³BASIC ³
+
−
³    RAM        ³        ³ 1 & 2  ³ 6 blocks ³    ³    ³    ³    ³      ³
+
−
ÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´ C000  ÀÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÁÄÄÄÄÁÄÄÄÄÁÄÄÄÄÄÁÄÄÄÄÄÄÙ
+
−
³stack/variables³      \
+
−
³---------------³ B000  | common RAM (accessible by all programs)
+
−
³    RAM        ³      /
+
−
ÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´ 8000                        ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
+
−
³              ³                            ³              ³
+
−
³    RAM        ³                            ³    PLS      ³
+
−
³              ³                            ³              ³
+
−
ÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´ 4000  ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿    ³    spell      ³
+
−
³              ³        ³OS- remaps high³    ³  checking    ³
+
−
³    RAM        ³        ³---------------³    ³    code      ³
+
−
³              ³        ³ Startup code  ³    ³              ³
+
−
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ 0      ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ    ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
+
−
 
+
−
general notes:
+
−
    most routines return carry set if successful
+
−
    unless otherwise stated assume AF corrupted, other regs preserved
+
−
    "all registers preserved" includes flags, but NOT alternate registers
+
−
    the ALTERNATE register contents can NEVER be assumed to be preserved
+
−
    (they are used as scratch registers in time critical routines)
+
−
 
+
−
 
+
−
==============
+
−
editbuf = B800
+
−
==============
+
−
line editor with options
+
−
zero-terminated string may be passed in buffer (HL)
+
−
this will display the initial contents
+
−
ENTRY - HL : pointer to input buffer
+
−
          B : size of buffer (excluding terminating zero)
+
−
                  A : flags.      b2=1 -> �� terminate entry
+
−
                                                  b3=1 -> input not echoed
+
−
                                                  b6=1 -> dotty background (character 176)
+
−
                                                  b5=1 -> edit unless characters entered
+
−
                                                  b4=1 -> delete trailing spaces
+
−
                                              Other bits must be set to zero.
+
−
EXIT  - c=0 z=1 ESC pressed
+
−
                c=1 z=1 empty string input
+
−
                c=1 z=0 at least one character entered
+
−
                HL preserved
+
−
                BC = last key token (or -1 if ESC used to terminate)
+
−
 
+
−
===================
+
−
kmcharreturn = B803
+
−
===================
+
−
returns a token to the keyboard buffer
+
−
ENTRY - BC = the token
+
−
EXIT - all registers preserved
+
−
 
+
−
================
+
−
kmreadkbd = B806
+
−
================
+
−
Gets a key token if there is one, does not wait
+
−
(Checks put back character and expands macros)
+
−
Returns tick event tokens if enabled
+
−
ENTRY - none
+
−
EXIT  c=1 : BC = token (B=0 for simple character)
+
−
      c=0 : no key token available
+
−
 
+
−
=================
+
−
kmreadchar = B9B3
+
−
=================
+
−
This routine is the same as kmreadkbd but macros are
+
−
exapnded and one or two other "behind the scenes" tasks
+
−
are performed. By using this routine you can be sure that
+
−
the Ctrl+Shift+S screen dump mechanism works in your code
+
−
 
+
−
==================
+
−
kmsetexpand = B809
+
−
==================
+
−
Defines a macro string
+
−
ENTRY - BC = macro token (between 256 and 383)
+
−
              - HL points to new macro string (first byte is the length,
+
−
                              followed by the string - need not be zero terminated)
+
−
EXIT  - c=1 if macro defined successfully
+
−
                c=0 if insufficient room in buffer
+
−
                      (The buffer size is user configurable)
+
−
 
+
−
=====================
+
−
kmsettickcount = B80C
+
−
=====================
+
−
Enables the ticker event
+
−
There are 100 ticks per second
+
−
When a ticker event occurs t.tickevent is returned by kmreadkbd
+
−
ENTRY - HL : number of ticks before first event
+
−
                DE : number of ticks between events
+
−
EXIT - all registers preserved
+
−
 
+
−
================
+
−
kmwaitkbd = B80F
+
−
================
+
−
Waits for a key token, uses kmreadkbd
+
−
(Checks put back character and expands macros)
+
−
Returns tick event tokens if enabled
+
−
ENTRY - none
+
−
EXIT  c=1 : BC = token (B=0 for simple character)
+
−
 
+
−
==============
+
−
readbuf = B812
+
−
==============
+
−
line editor. See also editbuf.
+
−
ENTRY - HL : pointer to input buffer (empty)
+
−
          B : size of buffer (excluding terminating zero)
+
−
 
+
−
EXIT  - c=0 z=1 ESC pressed
+
−
                c=1 z=1 empty string input
+
−
                c=1 z=0 at least one character entered
+
−
                HL preserved
+
−
                BC = last key token (or -1 if ESC used to terminate)
+
−
 
+
−
=================
+
−
testescape = B815
+
−
=================
+
−
tests whether an ESC key has been pressed (STOP or FUNCTION)
+
−
waits for a key if one is found in the keyboard buffer
+
−
ENTRY - none
+
−
EXIT  - c=1 if no ESC key in buffer
+
−
                c=1 if ESC key in buffer but STOP not pressed
+
−
                c=0 if ESC key in buffer and STOP then pressed
+
−
                A is preserved
+
−
 
+
−
===========
+
−
col1 = B818
+
−
===========
+
−
if cursor is at start of a line do nothing
+
−
otherwise move cursor to start of next line (within window)
+
−
ENTRY - none
+
−
EXIT  - none
+
−
 
+
−
===============
+
−
col1text = B81B
+
−
===============
+
−
same as textout, but calls col1 first
+
−
 
+
−
==============
+
−
textout = B81E
+
−
==============
+
−
displays string
+
−
ENTRY - HL : pointer to zero-terminated string
+
−
***************************************************************
+
−
WARNING - HL must not point into an upper ROM!
+
−
***************************************************************
+
−
EXIT  - none
+
−
 
+
−
===================
+
−
textoutcount = B821
+
−
===================
+
−
as textout, returns character count in B
+
−
 
+
−
=====================
+
−
txtclearwindow = B824
+
−
=====================
+
−
clears current window and moves cursor to top left
+
−
 
+
−
================
+
−
txtcuroff = B827
+
−
================
+
−
removes the cursor from the screen
+
−
ENTRY - none
+
−
EXIT  - all registers preserved
+
−
 
+
−
===============
+
−
txtcuron = B82A
+
−
===============
+
−
displays the cursor on the screen
+
−
ENTRY - none
+
−
EXIT  - all registers preserved
+
−
 
+
−
===================
+
−
txtgetcursor = B82D
+
−
===================
+
−
returns the cursor position
+
−
ENTRY - none
+
−
EXIT  - H = column (between 0 and 79)
+
−
                L = row (between 0 and 7)
+
−
===================
+
−
txtgetwindow = B830
+
−
===================
+
−
returns the window coordinates
+
−
ENTRY - none
+
−
EXIT  - H = left column (between 0 and 79)
+
−
                L = top row (between 0 and 7)
+
−
                D = right column (between 0 and 79)
+
−
                E = bottom row (between 0 and 7)
+
−
                c=0 if window is whole screen
+
−
                c=1 if a smaller window has been
+
−
 
+
−
================
+
−
txtoutput = B833
+
−
================
+
−
displays a character or acts on control code
+
−
ENTRY - A = character
+
−
                              A=7 : beeps  A=10 : LF  A=13 : CR
+
−
                              All other values displayed as character (PC char. set)
+
−
EXIT - all registers preserved
+
−
 
+
−
===================
+
−
txtsetcursor = B836
+
−
===================
+
−
moves the cursor
+
−
ENTRY - H = column (between 0 and 79)
+
−
                L = row (between 0 and 7)
+
−
EXIT - none
+
−
 
+
−
===================
+
−
txtsetwindow = B839
+
−
===================
+
−
defines a new window
+
−
ENTRY - H = left column (between 0 and 79)
+
−
                L = top row (between 0 and 7)
+
−
                D = right column (between 0 and 79)
+
−
                E = bottom row (between 0 and 7)
+
−
EXIT  - none
+
−
 
+
−
================
+
−
txtwrchar = B83C
+
−
================
+
−
displays a character
+
−
ENTRY - A = character. All values displayed (PC char. set)
+
−
EXIT - all registers preserved
+
−
 
+
−
======================
+
−
txtboldoff      = B83F
+
−
txtboldon      = B842
+
−
txtinverseoff  = B845
+
−
txtinverseon    = B848
+
−
txtunderlineoff = B84B
+
−
txtunderlineon  = B84E
+
−
======================
+
−
These six routines enable or disable various display
+
−
attributes. They have no entry conditions and preserve all registers.
+
−
 
+
−
==================
+
−
mcprintchar = B851
+
−
==================
+
−
sends a character to the printer
+
−
ENTRY - A=character
+
−
EXIT  - c=1 if successful
+
−
                c=0 if not sent
+
−
                A preserved
+
−
 
+
−
=====================
+
−
mcreadyprinter = B854
+
−
=====================
+
−
tests whether the printer is ready
+
−
ENTRY - none
+
−
EXIT  - c=0 if busy
+
−
                c=1 if ready
+
−
                A preserved
+
−
 
+
−
===================
+
−
mcsetprinter = B857
+
−
===================
+
−
sets the printer type to be used by mcprintchar and mcreadyprinter
+
−
ENTRY - A=printer type, 0=parallel, 1=serial
+
−
EXIT  - none
+
−
 
+
−
====================
+
−
padinitserial = B85A
+
−
====================
+
−
initialises the serial port using the global configured settings
+
−
turns on the UART and 4711
+
−
do not call this until needed - to prolong battery life
+
−
ENTRY - none
+
−
EXIT - none
+
−
 
+
−
==================
+
−
padinserial = B85D
+
−
==================
+
−
reads a character from the serial port
+
−
ENTRY - none
+
−
EXIT  - c=1 if successful, A=character
+
−
                c=0 if no character read
+
−
 
+
−
=====================
+
−
padoutparallel = B806
+
−
=====================
+
−
sends a character to the parallel port
+
−
ENTRY - A=character
+
−
EXIT  - c=1 if successful
+
−
                c=0 if not sent
+
−
                A preserved
+
−
 
+
−
===================
+
−
padoutserial = B863
+
−
===================
+
−
sends a character to the serial port
+
−
ENTRY - A=character
+
−
EXIT  - c=1 if successful
+
−
                c=0 if not sent
+
−
                A preserved
+
−
 
+
−
=======================
+
−
padreadyparallel = B866
+
−
=======================
+
−
tests whether the parallel port is ready
+
−
ENTRY - none
+
−
EXIT  - c=0 if busy
+
−
                c=1 if ready
+
−
                A preserved
+
−
 
+
−
=====================
+
−
padreadyserial = B869
+
−
=====================
+
−
tests whether the serial port is ready
+
−
ENTRY - none
+
−
EXIT  - c=0 if busy
+
−
                c=1 if ready
+
−
                A preserved
+
−
 
+
−
=====================
+
−
padresetserial = B86C
+
−
=====================
+
−
turns off the UART and 4711
+
−
call this when finished using the serial port to prolong battery life
+
−
ENTRY - none
+
−
EXIT - none
+
−
 
+
−
=======================
+
−
padserialwaiting = B86F
+
−
=======================
+
−
tests whether there is a character waiting to be read
+
−
      from the serial port
+
−
ENTRY - none
+
−
EXIT  - c=1 if character waiting
+
−
                c=0 if no character waiting
+
−
 
+
−
===================
+
−
padgetticker = B872
+
−
===================
+
−
returns the address of a 4 byte 100Hz ticker
+
−
ENTRY - none
+
−
EXIT  - HL is the address of the least significant byte
+
−
 
+
−
=================
+
−
padgettime = B875
+
−
=================
+
−
reads the time and date from the RTC
+
−
ENTRY - HL points to an 7 byte buffer to use
+
−
EXIT  - HL preserved
+
−
                      data returned as above (see padsettime)
+
−
 
+
−
==================
+
−
padsetalarm = B878
+
−
==================
+
−
sets the ALARM date and time (within next month)
+
−
ENTRY - HL points to 3 byte data area
+
−
                byte 0=date 1=hour  2=minute
+
−
EXIT  - none
+
−
 
+
−
=================
+
−
padsettime = B87B
+
−
=================
+
−
sets the RTC date and time
+
−
ENTRY - HL points to 7 byte data area
+
−
                bytes 0,1 = year (low,high)
+
−
                2=month  3=date
+
−
                4=hour  5=minute  6=second
+
−
EXIT  - none
+
−
 
+
−
==================
+
−
heapaddress = B87E
+
−
==================
+
−
obtains the address of a memory block for a given memory handle
+
−
ENTRY - DE = memory handle
+
−
EXIT  - HL = pointer to memory block
+
−
 
+
−
================
+
−
heapalloc = B881
+
−
================
+
−
allocates a block of memory from the heap
+
−
ENTRY - DE = number of bytes to allocate
+
−
EXIT  - HL = memory handle in range [1,63] if successful
+
−
                HL = 0 if failed
+
−
Note:  heapaddress must be used to get a pointer to the memory block
+
−
                Unless the block is locked with heaplock, heapaddress must be
+
−
                called each time the memory block is used. IT MAY HAVE MOVED!
+
−
 
+
−
===============
+
−
heapfree = B884
+
−
===============
+
−
frees a block of memory
+
−
ENTRY - DE = memory handle, returned by heapalloc or heaprealloc
+
−
EXIT  - none (preserves HL,BC)
+
−
Note: the memory handle passed must be a valid handle returned by
+
−
              heapalloc or heaprealloc. This is not validated.
+
−
 
+
−
===============
+
−
heaplock = B887
+
−
===============
+
−
locks or unlocks a memory block
+
−
ENTRY - DE = memory handle
+
−
                BC = non zero - the block is locked. It will not be moved
+
−
                          until unlocked so fixed addresses can be used as
+
−
                          pointers into the block
+
−
                BC = 0 - the block is unlocked
+
−
 
+
−
==================
+
−
heapmaxfree = B88A
+
−
==================
+
−
returns the largest block size that can be allocated
+
−
ENTRY - none
+
−
EXIT  - HL = largest free block size in bytes
+
−
 
+
−
==================
+
−
heaprealloc = B88D
+
−
==================
+
−
changes the size of an allocated memory block
+
−
ENTRY - DE = memory handle
+
−
                BC = new size for memory block
+
−
EXIT    HL = zero if failed to reallocate
+
−
                      The old block will not be freed but could have moved
+
−
                HL = non-zero if successful
+
−
Note: if the block is being expanded, it must be assumed that the
+
−
base of the memory block will be moved (even if the block cannot
+
−
actually be expanded) so heapaddress must be called afterwards.
+
−
If the block is being contracted, the base will not move.
+
−
 
+
−
=============
+
−
fclose = B890
+
−
=============
+
−
closes a file
+
−
ENTRY - DE = file handle
+
−
EXIT  - c=1 if successful, c=0 if failed
+
−
 
+
−
=============
+
−
ferase = B893
+
−
=============
+
−
erases a file
+
−
ENTRY - HL = zero-terminated filename
+
−
EXIT  - c=1 if OK, c=0 if error (file not found)
+
−
 
+
−
===============
+
−
finblock = B896
+
−
===============
+
−
reads a block from a file
+
−
ENTRY - DE = file handle
+
−
              - HL = buffer
+
−
              - BC = number of bytes to read (> 0)
+
−
EXIT  - c=1 if end of file not reached
+
−
              - c=0 if eof (or error?)
+
−
              - BC = number of bytes read
+
−
              - HL = address after last byte read
+
−
KNOWN BUG (1.00,1.01) - finblock does not set the file position
+
−
so repeated calls will always read from the start of the file
+
−
Workaround: call fseek after calling finblock to set the pointer
+
−
 
+
−
============
+
−
finchar B899
+
−
============
+
−
reads a byte from a file
+
−
ENTRY - DE = file handle
+
−
EXIT  - c=1 if successful, A=character
+
−
                c=0, A corrupt if end of file reached
+
−
              other regs preserved
+
−
 
+
−
================
+
−
findfirst = B89C
+
−
================
+
−
finds first file. setdta must have been called first
+
−
ENTRY - none
+
−
EXIT  - HL=0 if no files
+
−
              - HL points to file info structure if file found
+
−
              - 1st item in structure is the filename, zero-terminated
+
−
              -      (up to 12 characters long)
+
−
              - offset 13 is attribute byte
+
−
              - offset 14/15 is the file size in bytes
+
−
 
+
−
===============
+
−
findnext = B89F
+
−
===============
+
−
finds next file. findfirst must have been called first
+
−
ENTRY - none
+
−
EXIT  - HL=0 if no more files
+
−
              - HL as findfirst if file found
+
−
 
+
−
==============
+
−
fopenin = B8A2
+
−
==============
+
−
opens a file for input
+
−
ENTRY - HL points to zero-terminated filename
+
−
EXIT  - c=1 if successful, DE=file handle
+
−
                c=0 if failed (file not found)
+
−
              DE corrupt if error
+
−
              A corrupt, other regs preserved
+
−
 
+
−
===============
+
−
fopenout = B8A5
+
−
===============
+
−
opens a file for output
+
−
ENTRY - HL points to zero-terminated filename
+
−
EXIT  - c=1 if successful, DE=file handle
+
−
                c=0 if failed (out of memory/too many files/file exists)
+
−
              DE corrupt if error
+
−
              A corrupt, other regs preserved
+
−
 
+
−
==============
+
−
fopenup = B8A8
+
−
==============
+
−
opens a file for input and output.
+
−
the file must exist already
+
−
ENTRY - HL points to zero-terminated filename
+
−
EXIT  - c=1 if successful, DE=file handle
+
−
                c=0 if file not found
+
−
              DE corrupt if error
+
−
              A corrupt, other regs preserved
+
−
 
+
−
================
+
−
foutblock = B8AB
+
−
================
+
−
writes a block to a file
+
−
ENTRY - DE = file handle
+
−
              - HL = buffer
+
−
              - BC = number of bytes to write (> 0)
+
−
EXIT  - c=1 if OK
+
−
              - c=0 if error
+
−
              - BC = number of bytes written
+
−
              - HL = address after last byte written
+
−
 
+
−
===============
+
−
foutchar = B8AE
+
−
===============
+
−
writes a byte to a file
+
−
ENTRY - DE = file handle
+
−
              - A  = character
+
−
EXIT  - c=1 if successful
+
−
                c=0, A corrupt if end of file reached
+
−
              A corrupt, other regs preserved
+
−
 
+
−
==============
+
−
frename = B8B1
+
−
==============
+
−
renames a file
+
−
ENTRY - HL = zero-terminated old filename
+
−
              - DE = zero-terminated new filename
+
−
EXIT  - c=1 if OK, c=0 if error (file not found)
+
−
 
+
−
============
+
−
fseek = B8B4
+
−
============
+
−
moves the file pointer to a position within a file
+
−
ENTRY - DE = file handle
+
−
      - BC = offset from start of file
+
−
EXIT  - c=1 if successful
+
−
        c=0 if offset past end of file (pointer not changed)
+
−
KNOWN BUG (1.00,1.01) - leaves error messages enabled (fnoisy)
+
−
Workaround: call fquiet after fopenout if necessary
+
−
 
+
−
============
+
−
fsize = B8B7
+
−
============
+
−
finds size of file
+
−
ENTRY - HL = zero-terminated filename
+
−
EXIT  - c=1  HL=size in bytes, if found
+
−
              - c=0 if not found
+
−
 
+
−
==================
+
−
fsizehandle = B8BA
+
−
==================
+
−
finds size of an open file
+
−
ENTRY - DE = file handle
+
−
EXIT  - HL=size in bytes
+
−
 
+
−
============
+
−
ftell = B8BD
+
−
============
+
−
returns the value of the file pointer
+
−
ENTRY - DE = file handle
+
−
EXIT  - HL = current file position
+
−
 
+
−
===============
+
−
ftesteof = B8C0
+
−
===============
+
−
tests whether end of file has been reached
+
−
ENTRY - DE=file handle
+
−
EXIT  - c=1 if not eof, c=0 if eof
+
−
 
+
−
=================
+
−
selectfile = B8C3
+
−
=================
+
−
displays the file selector (clears the screen first)
+
−
shows all files and allows a selection to be made
+
−
using the cursor keys and RETURN
+
−
ENTRY - none
+
−
EXIT  - c=1 if a file selected (RETURN pressed)
+
−
                HL = filename
+
−
          - c=0 if STOP pressed
+
−
 
+
−
=============
+
−
setdta = B8C6
+
−
=============
+
−
set memory block to be used by findfirst/findnext
+
−
ENTRY - DE= address of buffer (at least 35 bytes long)
+
−
                      buffer must be in common RAM (8000h-BFFFh)
+
−
EXIT  - none
+
−
 
+
−
=================
+
−
fdatestamp = B8C9
+
−
=================
+
−
sets file date/time to current date/time
+
−
ENTRY - HL = zero terminated filename
+
−
EXIT  - c=1 if successful
+
−
              - c=0 if not found
+
−
 
+
−
===============
+
−
fsetattr = B8CC
+
−
===============
+
−
sets the attribute byte for a file open for output
+
−
if the file is open for input only there is no effect
+
−
ENTRY - DE = file handle
+
−
              - C  = attribute byte
+
−
                                      bit 0 = system file
+
−
                                      bit 1 = hidden file
+
−
                                      bit 2 = BASIC program
+
−
                                      bit 3 = binary file
+
−
EXIT  - c=1 if successful
+
−
              - c=0 if not found
+
−
 
+
−
===============
+
−
fgetattr = B8CF
+
−
===============
+
−
returns attribute byte of file
+
−
ENTRY - HL = zero-terminated filename
+
−
EXIT  - c=1  A=attribute, if found
+
−
              - c=0 if not found
+
−
              preserves HL
+
−
 
+
−
==================
+
−
kmgetyellow = B8D2
+
−
==================
+
−
ascertains whether a 'yellow event' is pending
+
−
(so called because the FUNCTION key is coloured yellow)
+
−
a yellow event occurs (i) when the user has pressed one of the
+
−
the FUNCTION+key combinations that cause an immediate context switch
+
−
(FN+red, FN+green, FN+blue, FN+menu)
+
−
or (ii) when the machine is powered up and (because the option to
+
−
preserve context has not been set) needs to return to the main menu
+
−
 
+
−
ENTRY -  none
+
−
EXIT  -  c=1, BC=token if yellow event pending
+
−
                  An application should exit normally as quickly as possible
+
−
                      Any UNSAVED FILES should be SAVED AUTOMATICALLY!
+
−
              -  c=0, BC=0 if no yellow event pending
+
−
 
+
−
Note: each of the yellow event keys return the ESC token (2FCh)
+
−
An application should call kmgetyellow whenever an ESC is read,
+
−
this distinguishes between a yellow event and an ordinary ESC.
+
−
 
+
−
==================
+
−
kmsetyellow = B8D5
+
−
==================
+
−
sets up a yellow event. Specialised use only.
+
−
ENTRY - BC = a yellow event token
+
−
EXIT  - none
+
−
 
+
−
=====================
+
−
lapcat_receive = B8D8
+
−
=====================
+
−
reads a character from the parallel port using Lapcat protocol
+
−
ENTRY - none
+
−
EXIT  - c=1 if successful, A=character
+
−
                c=0 if no character read
+
−
 
+
−
==================
+
−
lapcat_send = B8DB
+
−
==================
+
−
sends a character to the parallel port using Lapcat protocol
+
−
ENTRY - A=character
+
−
EXIT  - c=1 if successful
+
−
        c=0 if error
+
−
 
+
−
====================
+
−
padgetversion = B8DE
+
−
====================
+
−
gets the firmware version number
+
−
 
+
−
ENTRY - none
+
−
EXIT  - HL = version number (*100)
+
−
              Thus, 1.03 returns 103
+
−
 
+
−
==================
+
−
diskservice = BA5E
+
−
==================
+
−
calls a Ranger disk routine
+
−
 
+
−
ENTRY - C = number of routine to call
+
−
        A, HL, DE passed to the disk routine
+
−
EXIT  - c=1 if successful, HL may contain returned value
+
−
        c=0 if failed, A = error code (Ranger documentation)
+
−
 
+
−
        C = 0  r_test
+
−
            3  r_begin
+
−
            6  r_change_disk
+
−
            9  r_check_disk
+
−
            C  r_get_cd
+
−
            F  r_set_cd
+
−
            12  r_set_dta
+
−
            15  r_find_first
+
−
            18  r_find_next
+
−
            1B  r_save_file
+
−
            1E  r_retrieve_file
+
−
            21  r_set_attrib
+
−
            24  r_create_directory
+
−
            27  r_remove_directory
+
−
            2A  r_delete_file
+
−
            2D  r_rename_file
+
−
            30  r_finish
+
−
            33  r_disk_space
+
−
            36  r_install
+
−
            39  r_park_heads
+
−
            3C  r_format_track
+
−
            3F  r_format_done
+
−
            42  r_save_wordstar
+
−
            45  r_save_ascii
+
−
            48  r_begin_program
+
−
            4B  r_load_program
+
−
 
+
−
                System variables
+
−
                <<<<<<<<>>>>>>>>
+
−
 
+
−
The following are the RAM based variables used by the operating system. It
+
−
is hoped that they will always use these locations in subsequent versions
+
−
of the software - but this is not guaranteed.
+
−
 
+
−
B000  copyofmmu0      ds 1    ; copy of MMU0 since it's a write-only port
+
−
B001  copyofmmu1      ds 1    ; copy of MMU1 since it's a write-only port
+
−
B002  copyofmmu2      ds 1    ; copy of MMU2 since it's a write-only port
+
−
B003  copyofmmu3      ds 1    ; copy of MMU3 since it's a write-only port
+
−
                     
+
−
B004  gotcontext      ds 1
+
−
B005  __savepearlmmu  ds 1    ; extra vars needed in case we mustn't save context
+
−
B006  __saveaf        ds 2
+
−
B008  __savehl        ds 2
+
−
B00A  saveaf          ds 2    ; to save context, we need to save all the registers ...
+
−
B00C  savebc          ds 2
+
−
B00E  savede          ds 2
+
−
B010  savehl          ds 2
+
−
B012  saveix          ds 2
+
−
B014  saveiy          ds 2
+
−
B016  savepc          ds 2
+
−
B018  savesp          ds 2
+
−
B01A  saveafdash      ds 2
+
−
B01C  savebcdash      ds 2
+
−
B01E  savededash      ds 2
+
−
B020  savehldash      ds 2
+
−
B022  savemmu0        ds 1    ; ... and the memory state
+
−
B023  savemmu1        ds 1
+
−
B024  savemmu2        ds 1
+
−
B025  savemmu3        ds 1
+
−
B026  savecritpc      ds 2
+
−
B028  savecritsp      ds 2
+
−
B02A  savingcontext ds 1
+
−
B02B  nmimagic        ds 4
+
−
B02F  nmichksums      ds 8    ; checksum bytes of first 8 roms
+
−
B037  criticalpc      ds 2    ; save pc,sp for recovery from NMI during IRQ
+
−
B039  criticalsp      ds 2
+
−
                     
+
−
B03B                  ds 80  ; A small stack which we only use in initialisation.
+
−
                              ; It can't sensibly overlap with anything in case we get an NMI
+
−
                              ; requring immediate shut down after saving context.
+
−
                              ; Subsequent power on will have to restore the context
+
−
B08B  initstack
+
−
B08B  diagnostics?    ds 1    ; flag used in start-up, nonzero to do diagnostics
+
−
B08C  saveprinstat    ds 1
+
−
B08D  kbdstate1      ds 10  ; 1 bit per key, 1=down 0=up  corresponds to matrix
+
−
B097  kbdstate2      ds 10
+
−
 
+
−
PADKEYBUFLEN          equ 32          ; this MUST be 2^n for positive integer n
+
−
B0A1  padkeybuf      ds PADKEYBUFLEN*2
+
  
−
B0E1  padnextin      ds 1            ; offset into padkeybuf
+
  E0 = not used,  
−
B0E2  padnextout      ds 1
+
  E1 = data
−
B0E3  padbufempty    ds 1            ; nonzero if empty
+
−
B0E4  lastkbdstate    ds 2
+
−
B0E6  thiskbdstate    ds 2
+
−
B0E8  caps.state      ds 1            ; 0=off FF=on
+
−
B0E9  savecaps        ds 1
+
−
B0EA  justswitchedon? ds 1
+
−
                     
+
−
; variables above here are preserved after timeout
+
−
                     
+
−
                     
+
−
PADSERBUFLEN          equ 32          ; this MUST be 2^n for positive integer n
+
−
B0EB  padserbuf      ds PADSERBUFLEN
+
−
B10B  padsernextin    ds 1
+
−
B10C  padsernextout  ds 1
+
−
B10D  padserbufempty ds 1
+
−
B10E  padserin_xoff  ds 1    ; non-zero when XOFF has stopped inward transmission
+
−
B10F  padserout_xoff  ds 1    ; non-zero when XOFF has stopped outward transmission
+
−
B110  disablexonxoff  ds 1    ; nonzero to disable software handshake
+
−
                     
+
−
B111  ackirq          ds 1    ; set non-zero when ACK interrupt occurs
+
−
                     
+
−
B112  rptdelay        ds 1    ; centisecs
+
−
B113  rptrate        ds 1    ; centisecs
+
−
B114  rpttimer        ds 1    ; count down timer for key repeat
+
−
B115  keytorepeat    ds 1    ; key number
+
−
B116  rptkeystates    ds 1    ; shift states
+
−
                     
+
−
B117  rtcbuf          ds 13
+
−
B124  d.alarmday      ds 6    ; alarm day,hour,min ready for rtc chip
+
−
B12A  alarmhappened  ds 1    ; non zero when alarm has gone off, message pending
+
−
B12B  alarmhappenedgotmsg    ds 1    ; non zero when alarm has gone off, got message & pending
+
−
B12C  soundcounter    ds 1    ; non-zero if we're playing a tune
+
−
B12D  soundptr        ds 2    ; pointer to array of frequency,duration
+
−
B12F  soundrepcount  ds 1
+
−
B130  soundrepptr    ds 2
+
−
B132  poweroffminutes ds 1    ; configured time to power off
+
−
B133  minutesleft    ds 1
+
−
B134  minutecounter  ds 2
+
−
B136  eventhappened  ds 1
+
−
B137  preservecontext ds 1    ; 0=return to main screen at power on
+
−
B138  dontpreservecontext    ds 1    ; 1=dont preserve (diag/batt)
+
−
                     
+
−
B139  mainprog        ds 1    ; 6=inbasic, 128=inexternal (foreground program id)
+
−
B13A  currentprinter ds 1    ; 0 for parallel, 1 for serial
+
−
B13B  currentmenu    ds 2    ; pointer to current menu
+
−
B13D  wasmenusel      ds 1    ; after kmwaitchar this is 1 if menu used, 0 if not
+
−
                      ; need this in fsel to know whether redraw needed
+
−
                     
+
−
B13E  lastsecond      ds 1    ; checked to see whether to update the time
+
−
B13F  clockon?        ds 1    ; uses in Protext, non-zero when clock is enabled
+
−
                     
+
−
B140  sdumpname      ds 4    ; s.a, s.b, s.c etc. for screen dump name
+
−
                     
+
−
                      ; force d.workspace to an 8 byte boundary
+
−
B148  d.workspace    ds 8    ; for massaged copy of symbol data (eg inverse/underline)
+
−
                     
+
−
B150  d.datebuf      ds 9+MAXMONTHLEN        ; 27 January 1992
+
−
B162  d.asciitime    ds 12                  ; hh:mm:ss xm\0
+
−
                     
+
−
B16E  currentcfg      ds cfg.len
+
−
                     
+
−
B1BA  g.outstream    ds 1    ; bit 0 for screen, 1 for printer, 2 for file
+
−
B1BB  g.h.outfile    ds 2    ; file handle for charout if bit 2 set
+
−
B1BD  g.pos          ds 1    ; current column number (charout)
+
−
                     
+
−
B1CE  def.fname      ds      MAXPNLEN+1      ; Name of current file being edited
+
−
                      ; first byte not zero if document open
+
−
                      ; (yellow/red goes to edit mode, transfer from addrbook works)
+
−
B1DD  def.first      ds 1
+
−
                     
+
−
                     
+
−
      ; DO NOT CHANGE THE LAYOUT OF THE FIRST 21 BYTES
+
−
      0024            len.findinfo equ 36
+
−
      000D            o.findinfo.attr equ 13
+
−
      000E            o.findinfo.size equ 14
+
−
      0010            o.findinfo.time equ 16
+
−
      0012            o.findinfo.date equ 18
+
−
      0023            o.findinfo.mhandle equ 35
+
−
                     
+
−
B1DE  d.findinfobuf  ds len.findinfo
+
−
                     
+
−
      0002            o.file.size    equ 2
+
−
      0005            o.file.mhandle equ 5
+
−
      000D            o.file.attr    equ 13
+
−
                     
+
−
      000D            o.direntry.attr equ 13
+
−
      000E            o.direntry.size equ 14
+
−
      0010            o.direntry.time equ 16
+
−
      0012            o.direntry.date equ 18
+
−
                     
+
−
                     
+
−
;      char name[13];  /* 12 chars plus \0 (the file we found) */
+
−
;      char attribute;
+
−
;      uint size;              /* filesize can't be bigger than 64k */
+
−
;      uint time,date; /* if we allow time & date stamping */
+
−
;      char flags;            /* memory block flags */
+
−
;      char handle;    /* memory block handle */
+
−
                     
+
−
                      ;******************************************************************************
+
−
                      ; PEARL.TXT DATA
+
−
                     
+
−
;; The following 8 bytes are saved for each stream
+
−
                     
+
−
B202  d.thisstream    ds      8-8
+
−
B202  d.colrow        ds      2-2    ; keep next 2 together
+
−
B202  d.row          ds      1      ; 0-based within window
+
−
B203  d.col          ds      1      ;
+
−
                     
+
−
B204  d.winlefttop    ds      2-2    ; keep next 2 together
+
−
B204  d.wintop        ds      1
+
−
B205  d.winleft      ds      1
+
  
−
B206  d.winsize      ds      2-2    ; keep next 2 together
+
[http://groups.google.com/group/comp.sys.amstrad.8bit/browse_thread/thread/ce201414eff39a29/19cb6f7056d49480?lnk=gst&q=nc100+sound#19cb6f7056d49480  Russell Marks's notes about sound generation on NC100]
−
B206  d.winheight    ds      1      ; height -1
+
−
B207  d.winwidth      ds      1      ; width -1
+
−
                     
+
−
B208  d.winset?       ds      1      ; NZ if window
+
−
B209  d.state        ds      1      ; bit 7 if inverse on
+
−
                     
+
−
;; The following are recalculated from the above (in txtstrselect)
+
−
                     
+
−
B20A  d.colrowcount  ds      2-2    ; keep next 2 together
+
−
B20A  d.rowcount      ds      1
+
−
B20B  d.colcount      ds      1      ; how many more cols to print on this line
+
−
B20C  d.stream        ds      1      ; current stream number
+
−
B20D  d.fastpos      ds      2      ; needed for quick screen update
+
−
                     
+
−
                     
+
−
B20F  d.streamwsp    ds      8*NSTREAMS      ; 8 streams of 8 bytes each
+
  
−
B24F  d.dateptr      ds 2            ; non null for expanding time/date
+
[[NC100 IO Specification]]
−
B251  d.kmcharret    ds 2            ; Returned character
+
−
B253  d.kstate        ds 2            ; Key locks state
+
−
B255  d.caslocks      ds 1            ; Shift states set by sticky key press
+
−
B256  d.sticky        ds 1            ; non-zero in sticky key mode
+
−
B257  d.yellow        ds 1            ; low byte of yellow/other key token
+
−
                                      ; stored by p.xlattoken which then returns ESC
+
−
B258  d.calcmode      ds 1            ; nonzero if keyboard in calculator mode
+
−
                     
+
−
B259  d.kmexplen      ds 1            ; expansion string length
+
−
B25A  d.kmexpptr      ds 2            ; expansion string pointer
+
−
B25C  d.expbuffer    ds 2            ; address of expansion key buffer
+
−
B25E  d.expbufptr    ds 2            ; pointer to free byte
+
−
B260  d.expbufend    ds 2            ; last byte in buffer
+
−
                     
+
−
B2A1  macro_buf      ds 256
+
−
                     
+
−
; file selector variables
+
−
B3A7  fs_clicat      ds      1      ; non-zero if CAT command, not fsel
+
−
B3A8  fs_showsizes    ds      1      ; non-zero if showing file sizes (pad default=off)
+
−
B3A9  fs_showsys      ds      1      ; non-zero if showing system files
+
−
B3AA  fs_curfile      ds      1      ; current file number offset from top left
+
−
B3AB  fs_topleftfile  ds      1      ; file number displayed top left
+
−
B3AC  fs_numcols      ds      1
+
−
B3AD  fs_colwidth    ds      1
+
−
B3AE  fs_numshown    ds      1
+
−
B3AF  fs_maxfiles    ds      1      ; max files that can be shown
+
−
FS_NUMROWS            .equ    7      ; display rows
+
−
FS_NUMCOLS            .equ    5
+
−
FS_COLWIDTH            .equ    16
+
−
B3B0  fs_handle      ds      2
+
−
FS_NUMSHOWN            .equ    FS_NUMCOLS*FS_NUMROWS
+
−
                                ; number of files shown
+
−
B3B2  fs_numfilerows  ds      1      ; rows of files in CAT command
+
−
B3B3  fs_startlist    ds      2      ; start of file list
+
−
                      ; zero if doing unsorted list
+
−
B3B5  fs_startdir    ds      2      ; start of directory entries
+
−
B3B7  fs_endlist      ds      2
+
−
B3B9  fs_numfiles    ds      1      ; number of files in directory
+
−
B3BA  fs_lastshown    ds      1      ; last filenumber currently shown
+
−
                      ; fs_topleft + FS_NUMSHOWN
+
−
                     
+
−
B3BB  tickcount          ds 4    ; 32 bit counter needed for basic
+
−
B3BF  ticksleftuntilevent ds 2
+
−
B3C1  tickreloadvalue    ds 2
+
−
B3C3  tickeventpending    ds 1
+
−
B3C4  countdowntimer      ds 2
+
−
                     
+
−
B3C6  savestream      ds 1
+
−
                     
+
−
B3C7  password        ds 5    ; encrypted
+
−
B3CC  pwbuf          ds 5    ; clear
+
−
B3D1  realpwbuf      ds 5    ; the real password saved for encrypting
+
−
B3D6  haspassword    ds 1    ; non-zero if has password
+
−
                      ;passwdmsg ds 2
+
−
B3D7  passwdlen      ds 1
+
−
B3D8  passwordlocked  ds 1    ; non-zero if locked (disallow soft reset)
+
−
B3D9  editingsecret  ds 1    ; non-zero when editing secret file (can't delete it)
+
−
B3DA  inmenu?        ds 1    ; non-zero when inside menu - macros disabled
+
−
                     
+
−
B3DB  macro_count    ds      1
+
−
B3DC  recording?      ds      1
+
−
B3DD  macro_token    ds      2
+
−
                     
+
−
B3DF  printfailed    ds 1            ; flag set by mccheckprinter
+
−
                      ; stops "finished printing" message
+
−
B3E0  wasmemoryerr    ds 1
+
−
B3E1  inprotext      ds 1            ; used in file selector, 0=was Fn-L, nonzero=Fn-2
+
  
−
**** End ****
+
[[Category:NC Series]]

Latest revision as of 13:18, 25 June 2023

This update to NCIOSPEC.TXT covers the differences between the NC100 hardware (documented in the original NCIOSPEC.TXT below) and the NC150/NC200 hardware.

This information was discovered mainly by Russell Marks during development of his NC emulator and ZCN software, with the remaining information found by myself during development of my NC200 emulation for M.E.S.S.

This update does not cover the NC150. I do not have details of any differences between this and the NC100 at this time.

When I have information on this system, it will be documented here.

These have been worked out by dissassembling the rom, and looking at patterns of I/O read/writes.

  • The NC200 does not have a TC8521 Real Time Clock, instead it has a MC146818 Real Time Clock. The MC146818 is no longer produced now, but is part of many PC designs.
  • The NC200 has a NEC765 compatible floppy disc controller. The disc interface was designed by Ranger Computers.

The ports listed in this section are different or have additional information to the NC100 port definitions. The other ports have the same function as the NC100.


  • The NC100 clock speed is 4.606MHz, at this time it is unknown if the NC200 has a different clock speed.
  • The NC100 on/off button generates an NMI.
  • The NC200 on/off button generates a maskable interrupt.

Keyboard NC100: 

B0: 
bit 0: Shift (Left)
bit 1: Shift (Right)
bit 2: unused
bit 3: Cursor Left (Red)
bit 4: Return
bit 5: unused
bit 6: unused
bit 7: unused

B1:
bit 0: Function (Yellow)
bit 1: Control
bit 2: Stop
bit 3: Space
bit 4: unused
bit 5: unused
bit 6: 5
bit 7: unused

B2: 
bit 0: Caps Lock
bit 1: Symbol
bit 2: 1
bit 3: Tab
bit 4: unused
bit 5: unused
bit 6: unused
bit 7: unused

B3:
bit 0: 3
bit 1: 2
bit 2: Q
bit 3: W
bit 4: E
bit 5: unused
bit 6: S
bit 7: D

B4:
bit 0: 4
bit 1: unused
bit 2: Z
bit 3: X
bit 4: A
bit 5: unused
bit 6: R
bit 7: F

B5:
bit 0: ??
bit 1: ??
bit 2: B
bit 3: V
bit 4: T
bit 5: Y
bit 6: G
bit 7: C

B6:
bit 0: 6
bit 1: Cursor Down (Blue)
bit 2: Del
bit 3: Cursor Right (Green)
bit 4: \
bit 5: /
bit 6: H
bit 7: N

B7:
bit 0: =
bit 1: 7 
bit 2: ~
bit 3: Up
bit 4: Menu
bit 5: U
bit 6: M
bit 7: K

B8:
bit 0: 8
bit 1: -
bit 2: )
bit 3: (
bit 4: "
bit 5: I
bit 6: J
bit 7: ,

B9:
bit 0: 0
bit 1: 9
bit 2: Del
bit 3: P
bit 4: :
bit 5: L
bit 6: O
bit 7: .




Address                 Comment                 	R/W 
=======                 =======                 	===

00			Display Memory start		W
20			Memory card wait state		W
A0			Card Battery status		R
60			Interrupt Request Mask		W
70			on/off control			W		
80			Printer Status			R					
90			IRQ Status			R
B0-B9			Key data in			R
D0-D1			MC146818 Real Time Clock	R/W
E0	                NEC765 Status          		R
E1			NEC765 Data			R/W


Address = 00 Write only start address of display memory 


bit 7           A15
bit 6           A14
bit 5           A13
bits 4-0        Not Used

Address = 20 Write only Memory card wait state control 

bit 7: memory card wait state control:  1 for wait states, 0 for no wait
bit 0: NEC765 Terminal Count input (1=TC active, 0=TC inactive)

Address = 30 Write only Floppy motor control 

bit 3: Floppy motor: 1=off, 0=on

Address = 70 on/off control 


bit 2: Backlight: 1=off, 0=on
bit 0: on/off control: 1 = on, 0 = off


Address = 80 centronics status 

bit 0: busy state

Address = A0 Card battery status 


bit 7: memory card present 0 = yes, 1 = no
bit 6: memory card write protected 1 = yes, 0 = no
bit 5: lithium battery 0 if >= 2.7 volts
bit 4: input voltage = 1, if >= to 4 volts
bit 3: ** unknown use **
bit 2: alkaline batteries. 0 if >=3.2 volts
bit 1: ** unknown use **
bit 0: battery power: if 1: batteries are too low for disk usage, if 0: batteries ok for disc usage

Address = B0 - B9 Read only Keyboard data 


B0..B9          each key of the 64 on the keyboard
                       will set a bit in one of these bytes
                       while pressed.

Russell Marks confirms that reading B9 does not clear the key scan interrupt like it does on the NC100. The interrupt must be explicitly cleared!

Address = 60 Write only Interrupt request mask 


bit 7:		** unknown use **
bit 6: 		** unknown use ** (Real Time Clock Alarm?)
bit 5:		NEC765 FDC
bit 4:		Power off interrupt
bit 3           Key scan
bit 2           TC8251 Serial Interrupt (Tx Ready OR Rx Ready)
bit 1           ** unknown use ** (not checked by OS - not used?)
bit 0           ACK from parallel interface

Address = 80 Printer status 

bit 7..1:	* unknown use *
bit 0:		printer busy status

1 = busy

Address = 90 Read/Write IRQ status 


bit 7:		** unknown use **
bit 6: 		** unknown use ** (Real Time Clock Alarm?)
bit 5:		NEC765 FDC
bit 4:		Power off interrupt
bit 3           Key scan
bit 2           TC8251 Serial Interrupt (Tx Ready OR Rx Ready)
bit 1           ** unknown use ** (not checked by OS - not used?)
bit 0           ACK from parallel interface

Address = D0/D1 MC146818 Real Time Clock

Consult MC146818 datasheet.


Address = E0/E1 NEC765 floppy disc controller

Consult NEC765 datasheet.

Read: 

E0 = Status, 
E1 = data

Write: 

E0 = not used, 
E1 = data

Russell Marks's notes about sound generation on NC100

NC100 IO Specification

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