Changes
/* Gate Array Register 2 - Video Mode, ROM enable, LEDs */
|#DFXX||%xx0xxxxx xxxxxxxx||[[Upper ROM Bank Number]] (bank 3 = Aleste Bootmenu)|| - ||Write
|-
|#EEXX||%xxx0xxx0 xxxxxxxx||Aleste [[8251 USART chip]] (RS232/Mouse) Data|| ? Read ||Write
|-
|#EFXX||%xxx0xxx1 xxxxxxxx||Aleste [[8251 USART chip]] (RS232/Mouse) Control/Status|| ? Read ||Write
|-
|#F4XX||%xxxx0x00 xxxxxxxx||[[8255]] PIO Port A (PSG/8253 Timer/Real-Time Clock data)||Read||Write
|-
|#FA7E||%xxxxx0x0 0xxxxxxx||Floppy Motor Control (for [[765 FDC]])|| - ||Write
|-
|#FABC||%xxxxx0x0 10xxxx00||Aleste EXTPORT with CS53: Forward PPI Port A to 8253 Timer 0|| - ||Write
|-
|#FABD||%xxxxx0x0 10xxxx01||Aleste EXTPORT with CS53: Forward PPI Port A to 8253 Timer 1|| - ||Write
|-
|#FABE||%xxxxx0x0 10xxxx10||Aleste EXTPORT with CS53: Forward PPI Port A to 8253 Timer 2|| - ||Write
|-
|#FABF||%xxxxx0x0 10xxxx11||Aleste EXTPORT with CS53: Forward PPI Port A to 8253 Control|| - ||Write
|-
|#FABF||%xxxxx0x0 10xxxxxx||Aleste EXTPORT|| - ||Write
|''bit''||Action
|-
|7||not used|-|6||not used|-|5||if 0, then AY is accessed when read/write to 8255 port A, if 1 then real-time clock is accessed with read/write to 8255 port A. When real-time clock is selected, bits 2..0 of PPI port C are used to define real-time clock operation. DS bit 2, AS bit 1, R/W bit 0. So combinations are 2, write address, 4 write data, 5 read data.
|-
|5-4||Enable PPI Port A usage* 0 = PSG (Sound Chip; default, as in CPC) (With PPI.Port C: BC1/BDIR)* 1 = Reserved (would access both PSG and 8253 timertogether)* 2 = RTC (Real-Time Clock) (With PPI. Any IPort C: Bit2=DS, Bit1=AS, Bit0=R/O W. So combinations are 2, write address, 4 write then accesses 8253 with data comming from 8255 port A. Bit A0, 5 read data)* 3 = 8253 (Baudrate/Future Timer) (With address lines A0 and A1 of I/O port defines 8253 = registerselection)
|-
|3||force video to black
|''bit''||Action
|-
|7||01
|-
|6||10
|-
|5||CAPS LED
07h AMSDOS (bytes in 8000h..BFFFh in the Aleste's 64K EPROM)
All other values 01h..02h, 04h..06h, 08h..FFh do select BASIC, too.
The BOOTMENU is an aleste specific ROM bank. BASIC and AMSDOS are 1:1 same as in CPC6128. The BIOS (lower ROM bank) is almost same as in CPC6128 (only the Startup Message and Printer handling are modified). For details, see:
* [[Media:AlesteBiosDisassembly.txt]] - Disassembly of differences between CPC6128 and Aleste BIOS
* [[Media:AlesteBootmenuRomBank3.asm]] - Original source code for BOOTMENU (Upper ROM Bank 3)
== PPI 8255 ==
The built-in RS232 port can be used to connect a serial mouse.
* See [[Serial RS232 Mouse]] for details on the protocol
[[Category:Non CPC Computers]][[Category:Clones]]
