1 /TEST
0 VSYNC (identical to CPC)
=== Z8536 CIO===
The Z8536 CIO chip is a counter and I/O chip. In the KC compact system it is used to generate interrupts, access to the parallel printer port, and possibly video control.
In the KC Compact:
* Port A is setup as I/O and is connected to the parallel printer port * Port B is setup as timer and is connected to the video hardware (?) * Port C is setup as timer and is connected to the Interrupt hardware
On start-up, the KC compact programs the z8536 to the following state:
* Port A: I/O mode: all bits are set to output, and bit 7 is inverted when writing. (bit 7 is /strobe signal to printer) * Port B: Counter mode (port B is split into two counters, both are setup the same): continuous count, restarts when count is over, uses external trigger, uses external input to update count, pulse output (when count is over) * Port C: Counter mode: same configuration as port B.
Port C is used to generate interrupts. The counter input is HSYNC (the counter counts counter-input transitions; low-high and high-low). The trigger input is VSYV (this signal is derived from VSYNC).
What this means:
* The Z8536 Port C counter is updated when HSYNC changes state * The Z8536 Port C counter is reset when VSYV changes state
With the default settings, the Z8536 will count 26 HSYNC transitions (52 lines of the display covered in this time) and generate a interrupt. At VSYNC the counter is reset so that the interrupts are synchronised.
CPC Interrupts:
* synchronised to 2 HSYNCs after VSYNC * interrupts cannot be generated closer than 32 lines * counter inside Gate Array counts up to 52 lines. * interrupt can be cleared by writing to bit 4 of Mode/ROM register in Gate Array (counter is also reset at this time)
KC compact interrupts:
* interrupt can be cleared by writing to bit 4 of Mode/ROM register at 0x07fxx (counter is *not* reset at this time) * interrupt system fully programmable: can count HSYNCS, or count internal Z8536 clocks!
Therefore, the KC compact interrupt system is more powerful than the CPC!
Data transfer stage (repeat for 256 bytes) Data byte transfer repeat 8 times (once for each data bit)
* write 0x0ff: DATA2="1",DATA7="1", and wait for /STROBE to read as "1" * read inputs: DATA1=data bit
Data byte acknowledge stage write: 0x0f0: DATA2="0", DATA7="1", and wait for /STROBE to read as "1"
* /STROBE and DATA1 are inputs * DATA2 and DATA7 are outputs
== Connecting a KC compact to a CPC+ monitor==
These connections are known to work!
What you need:
* SCART plug * 8-pin DIN socket
Lead connections:
* Connect the 8-pin DIN socket to the 8-pin DIN plug from the monitor * Connect the SCART plug to the SCART socket on the back of the KC Compact
Signal connections:
