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How It Was: Programming (and debugging) microprocessors

Clive Maxfield
11/18/2011 04:46 PM EST

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Bellhop
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re: How It Was: Programming (and debugging) microprocessors
Bellhop   11/28/2011 7:44:01 PM
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I too started out with the 1802. It was THE CMOS processor of the time. I hand-assembled on a legal pad and entered the data into my homemade development system rack. I had a hex keypad, hexadecimal readout (address and data), and a simple homemade debug monitor. There were some Phi-Decks laying around, so I used them to store my data. The 1802 ran the Phi-Deck too. I did a program up to 8K using this method. The Phi-Deck beat the heck out of paper tape and direct address entry with auto-increment made entering code easier. The keypad/display could also be used for data I/O during debugging and there was a single step mode and a breakpoint.

Phil16v
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re: How It Was: Programming (and debugging) microprocessors
Phil16v   11/22/2011 8:41:40 AM
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I joined a very small company in the East Midlands (UK) in January 1979, which had no electronics department, but a requirement for some unique electronic products. They had purchased a National COPS development system, which had a hex keypad and a 7 segment display. I refused to use it, since I considered the processor inadequate for their needs, and bought a Nascom (Z80 based) kit instead. After buying the £100+ 32k dynamic RAM card kit, and the ZEAP editor assembler on ROM, I bought a Vero board, which was at at that time available with an 80 way single sided edge connector, the same as the edge connector on the RAM card and the NASCOM. I then built an 'emulator' of sorts. Address and data areas that weren't used on the main board or the RAM card were mapped out onto a 40 way ribbon cable with a 40 pin DIL plug on the end of it which was the same pinout as the Z80. A home brewed EPROM programmer was added so that I could put my developed programs into the finished hardware, and the cassette tape data storage was replaced by a 5.25" single-sided 360k floppy drive, with a ROM based disk storage system called NAS-DOS. It wasn't really a disk operating system, since it required the user to specify the area of memory to copy to or from, and the sector and track numbers to access on the disk, but it was reliable. I was so pleased with the whole system that I built another for use at home. I recall that at the time the Intel SDK with ICE was about £11k, so it was very cost effective. I still have it somewhere - reading this article has re-kindled my determination to dig it out and recommission it. I wonder if you can still buy those floppies...

David Ashton
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re: How It Was: Programming (and debugging) microprocessors
David Ashton   11/19/2011 3:18:43 AM
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Wow.... I played around with an SDK-85 and also with an Osborne-1 years ago. I did some stuff on 8085s and Z80s but I remember looking at the MDS and other development stuff in my intel books (which I still have) and thinking how great it would be to have something like that. Great article, Aubrey, many thanks.

Max The Magnificent
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re: How It Was: Programming (and debugging) microprocessors
Max The Magnificent   11/18/2011 5:10:07 PM
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This is fantastic Aubrey -- thank you so much for taking the time to pull this together... ...I had forgotten the process of two-pass assembly using paper tapes, but I used to do this myself... the thing is that it really isn't all that long ago that we were doing this sort of thing -- things certainly have advanced dramatically...

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