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smdprutser / IEC-printer

Connects a thermal printer to vintage Commodore computers using the IEC bus
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open command needs secondary address? #1

Open abzman opened 3 years ago

abzman commented 3 years ago

I've been reading the various documentation on how commodore printers are supposed to work (like this: https://archive.org/details/Printer_Book_for_the_Commodore_64_and_VIC-20/page/n31/mode/2up)

From what I've seen this program should work: 10 OPEN 4,4 20 PRINT#4,"HELLO" 30 PRINT#4 40 CLOSE 4

But I get nothing out of the IEC printer, until I change the first line to: 10 OPEN 4,4,0 (or 4,4,1 or 4,4,7)

It seems that your code needs a defined secondary address and real commodore hardware of the time did not require that last parameter and it was implied that if you sent 4,4 you intended that to mean the same as 4,4,0.

Does this make sense? It took me a long time to figure out why none of the example printer programs were working.

smdprutser commented 3 years ago

Afaik it needs the second address to work properly ATM.

It is hard to detect the open when there is no secondary address (the commodore doesnt sent a open on the IEC bus in this case). will give it some thoughts later on.

abzman commented 3 years ago

You may be right, I'll have to get off my butt and hook up my real IEC printer