ORDIO.DOC

ORDIO.DOC - ORDINATOR I/O port documentation

;140210 Expanded from book and schematics. L
;211002 Expanded from DIAMOND listings. L
;161002 Created from memory. L

I/O ports

40-42	Temporary serial and cassette ports.		Read/Write

C6	RTC address port.				Write

C7	RTC data port.					Read/Write

DA	Floppy changed port.				Read/Write

DB	Floppy control port.				Read/Write

DC-DF	Floppy controller (1791).			Read/write

E7	DIP switches.					Read-only

EC-ED	Video card 0 controller (6845).			Read/Write

EE-EF	Video card 1 controller (6845).			Read/Write

F0-F3	Serial port interface (2651).			Read/Write

FC	Printer status port.				Read-only

FD	Printer data port.				Write-only

FE	EPROM programmer control port.			Read/Write

FF	MMU segment program.				Write-only
	A write to this port will program
	segment [A12-A15] from written data.

FF	CP/M mode enable.				Read-only
	A read from this port will enable
	CP/M mode where [0000..00FF] is
	no longer specially mapped to CPU ROM.