|
SVI MSX R/W Description 10 91 W Centronics Printer Data (characters out ASCII) 11 90 W Centronics STROBE output (bit 0=0) 12 90 R Centronics BUSY state (bit 0=1) 20 -- R Modem UART 8250 Receive buffer register 20 -- W Modem UART 8250 Divisor latch (LSB) 20 -- W Modem UART 8250 Transmitter holding buffer register 21 -- W Modem UART 8250 Divisor latch (MSB) 21 -- W Modem UART 8250 Interrupt enable register 22 -- W Modem UART 8250 Interrupt identification register 23 -- W Modem UART 8250 Line control register 24 -- W Modem UART 8250 Modem control register 25 -- R Modem UART 8250 Line status register 26 -- R Modem UART 8250 Modem status register 28 -- R RS-232C UART 8250 Receive buffer register 28 -- W RS-232C UART 8250 Divisor latch (LSB) 28 -- W RS-232C UART 8250 Transmitter holding buffer register 29 -- W RS-232C UART 8250 Divisor latch (MSB) 29 -- W RS-232C UART 8250 Interrupt enable register 2A -- W RS-232C UART 8250 Interrupt identification register 2B -- W RS-232C UART 8250 Line control register 2C -- W RS-232C UART 8250 Modem control register 2D -- R RS-232C UART 8250 Line status register 2E -- R RS-232C UART 8250 Modem status register -- 80 R/W RS-232C UART 8251 Data Port -- 81 R/W RS-232C UART 8251 Command/Status Port -- 82 R RS-232C Status Sense Port: CTS, CTC Channel-2, RI, & CD. -- 82 W RS-232C Interrupt Mask Register -- 83 RS-232C Reserved -- 84 R/W RS-232C CTC 8253 Counter 0 -- 85 R/W RS-232C CTC 8253 Counter 1 -- 86 R/W RS-232C CTC 8253 Counter 2 -- 87 W RS-232C CTC 8253 Mode Register 30 D0 R FDC WD1793 Status register 30 D1 W FDC WD1793 Command register 31 D2 R/W FDC WD1793 Track register 32 D3 R/W FDC WD1793 Sector register 33 D4 R/W FDC WD1793 Data register 34 D5 R FDC Read INTRQ and DRQ from FD-1793 34 D6 W FDC Disk select register (bit 0 and 1) 38 D7 W FDC Density select register (bit 0) 50 78 W CRT 6845 Adress latch 51 79 R CRT 6845 Controller register R0-R17 58 79 W CRT 6845 Bank control on/off 6C -- R/W PIO Interface highest 8 bits 6D -- R/W PIO Interface lowest 8 bits 80 98 W VDP TMS9918A Writes a byte to VRAM, increases VRAM pointer 81 99 W VDP TMS9918A Adress latch 84 98 R VDP TMS9918A Reads a byte from VRAM, increases VRAM pointer 85 R VDP TMS9918A 88 A0 W PSG AY-3-8910 Adress latch 8C A1 W PSG AY-3-8910 Data write 90 A2 R PSG AY-3-8910 Data read 98 A8 R PPI 8255 Port A 98 A8 W PPI 8255 Port A 99 A9 R PPI 8255 Port B 99 A9 W PPI 8255 Port B 96 AA R PPI 8255 Port C 96 AA W PPI 8255 Port C 97 AB W PPI 8255 Mode select and I/O setup of A,B,C 9A AB R PPI Return Mode
Source: Tomas Karlsson |
||
|
