#11
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Hi Grant;
I would be interested in the above listing and programs. Thank You Marty |
#12
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Quote:
Quote:
Paul |
#13
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Interestingly I've searched the web for altair programs and found nothing useful. I find that pretty amazing. Well, I've written a number of programs already using the switches, so I took a crack at my own echo program. I would have guessed the program to echo characters would be:
IN 11 011 011 021 00 010 001 OUT 11 010 011 021 00 010 001 JMP 11 000 011 0 00 000 000 00 000 000 So I keyed this in via the switches and then tried every possible configuration of windows hyperterminal I could think of, all 9600 baud, with various partty, flow control, and stop bits settings. I've tried it with and without a null modem cable. No go. Either my program is wrong (highly likely because I used port 021 which is for data and not port 020 which is for control). But I can't find decent descriptions of how the IO ports actually work. I wonder if the documentation was easier to come by in 1975. Or you could just attend the local computer club group. Paul |
#14
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You have to reset the port and send a config byte. You also have to check if there is data waiting in the chip buffer before you try to read the serial chip.
You SHOULD check to make sure that the TRANSMIT buffer is empty before transmitting a byte, but for this test we can assume that since you first have to wait for a byte that there will be more than enough time to transmit it before a new byte has been received. Do you understand that? Here is a sample program I just wrote. Sometime saturday night I'll get the program from my S-100 book to you. Code:
;Serial echo program for the 8080 and 2SIO ; .EQU CONT,0 ;CONTROL/STATUS PORT OF 2SIO CARD .EQU DATA,1 ;DATA PORT OF 2SIO CARD ; ; RESET: MVI A, H'03 ;MASTER RESET OUT CONT MVI A, H'15 ;CLK/16, 8N1, RTS LOW TX/RX INTERRUPTS DISABLED OUT CONT LOADLP: IN CONT ;WAIT FOR RX BUFFER TO BE FULL ANI H'01 JZ LOADLP IN DATA ;GET DATA OUT DATA ;SEND DATA JMP LOOP |
#15
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ECHO Program
Hi Paul;
I Don't have my notebook here with me, So I had to look it up on the net !!! I didn't take the time to look at all there was, but this should get you started. 000 333 input 001 000 or 020 or what ever port you have 002 017 003 332 004 000 005 000 006 333 007 001 or 021 or what ever port you have 010 323 011 001 or 021 or what ever port you have or 377 if you want to use the sense switches. 012 303 013 000 014 000 (This is in octal) Good Luck Marty |
#16
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H in the above program means "hex", don't treat those values as octal!
Back in the old days there were magazines and journals for programming help. Programming a computer was just the way you did things. There was basic, but in the earliest days no one even had that! So in order to survive you just had to learn it by whatever way possible. The most exciting thing about the kits that I build is the idea that I'm helping preserve some of the knowledge and allowing people to experience these things! |
#17
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Marty, you should initialize the port first. It may happen that sometimes it works but that could be just luck. You can't ever count on things being right inside the chips.
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#18
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yipee!!!! My card works. I tried your program, Grant. Here are the octal codes for it (assuming you start it at 000):
000 076 001 003 002 323 003 020 004 076 005 025 006 323 007 020 010 333 011 020 012 346 013 001 014 312 015 010 016 000 017 333 020 021 021 323 022 021 023 303 024 010 025 000 I have not tried your program yet, Marty. I'll give that a go tomorrow. Thanks, guys! Paul |
#19
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Now, even though you were basically doing what a robot could do...building the board...doesn't it just give you a great feeling of accomplishment!?
When that thing is booting basic using your several thousand solder joints all the pain and suffering will have been worth it. |
#20
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Paul, what kinds of other programs have you made? What resources did you used to do it? Any tips and hints for other people in your situation?
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