>I've got the SAM parallel interface, but I've lost my instructions.
>Can anyone tell me how to read/write from it? Thanks...
Something along the lines of:
;entered with data to print in E
LD BC,printerport+257 (usually 232, could be 234 though)
wnotbusy: IN A,(C)
RRA
JR C,wnotbusy ;if bit 0 = set, then it's still busy, so loop
OUT (C),B ;make sure that strobe line is high..
DEC B
DEC C
OUT (C),E ;output data to output latch
INC C
OUT (C),B ;make strobe line low
INC B
OUT (C),B ;make strobe line high...
RET
you can put an additional test at the START of your printer routine, before
you do anything else for:
LD BC,printerport+1
IN A,(C)
RRA
JR C,error ;if set, printer is busy. But we're not printing anything! so
;the printer is most likely not online... tell the user that
;the printer is off line
;rest of routine...
Can someone check if I've got the busy bit polarity right? :)
Simon
-!- Mains Hum: A sine of the times???
+- Email:[EMAIL PROTECTED] ---- Fidonet: 2:250/124.2 (Simon Cooke) -+
| Snail:1 Dovey Close, Astley, Tyldesley, Manchester, M29 7NP, UK |
| Tel: (01942) 886084 Fax: (01942) 886084 (ring voice first to confirm!)|
+- WWW: http://jumper.mcc.ac.uk/~simonc ----------------------------------+
