Anybody got ROMs for a Prompt-80

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scott baker

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May 30, 2025, 8:40:56 PMMay 30
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I got a prompt-80 on the way, but without its CPU board or ROMs. The CPU board I can find. But I'm not sure about the ROMs. I'm assuming they're something custom meant to work on the front panel of the prompt-80.

Anybody got em?

Scott

Raymond Jett

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May 31, 2025, 5:18:52 AMMay 31
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I have a Prompt 80... need to see what the EPROMs are in there. If they are 2716 I can dump them... but if they are 2708, I'll have to fix my Data I/O Series 22 first.

scott baker

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May 31, 2025, 11:30:36 PMMay 31
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They are 2708. I did find a set at http://www.bitsavers.org/pdf/intel/prompt80/firmware/ and there's also a user on VCF, Hans, who also seems to have the same set.

So I think I'm good now.

Wouldn't mind a hardware manual and a schematic, if anyone has one handy...

Scott

scott baker

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Jun 14, 2025, 10:57:51 PMJun 14
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My Prompt-80 is alive!

I found a CPU board for about $60 on eBay, and used the ROMs from Hans, a fellow VCF member. I did have to pull the power supply and recap it, as I was only seeing 0.8V on the 5V rail.

Now, does anyone have a copy of the manual? or some usage notes? I managed to figure out some of the obvious things, such as how to display/edit memory and registers. I know there's a bunch of "functions", but I don't know what they do.

Scott

prompt-80-startup-1024.JPG

andre...@gmail.com

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Jun 14, 2025, 11:39:04 PMJun 14
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Hi Scott,

 

I remember that in one of the intel databooks in the development section, there was an expanded cut sheet for the prompt 80 and it listed the commands.   That is the only documentation that I have seen.

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andre...@gmail.com

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Jun 14, 2025, 11:40:31 PMJun 14
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It seems that I have already scanned those pages on my computer, see attached.

Prompt 80-85.pdf

William Beech

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Jun 15, 2025, 2:29:58 PMJun 15
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Scott,

Good work.  I do not have the manual.  If you find one, please share it!

Bill
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scott baker

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Jun 15, 2025, 3:11:46 PMJun 15
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Thanks Andrew, that document is a big help -- at least now I have the function numbers.

I'm curious if it has any interface over serial (other than the read/write tape describe in the document). Document seems to imply that it might, but it wasn't completely clear. Even if it's just mimicking the keypad over serial, that would be useful.

I do have this random desire to add either Basic or Forth to it. There are Tiny Basic variants that would just about fit in the 1-2K of spare EPROM space. RAM is tight though, at only 1K of available RAM.

Scott

scott baker

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Jun 16, 2025, 2:35:11 AMJun 16
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Using function F1 I was able to write a tape (aka send a hex file out the serial port), so clearly I have serial working.

I was not so luckiy using F0 to read a tape from the serial port though. I would see a brief pause followed by an error. A little bit of disassembly suggests that it toggles DTR to start the paper tape and then it expects a character to show up very shortly thereafter. I can probably make it work if I want to.

Scott

scott baker

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Jun 30, 2025, 1:44:21 AMJun 30
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My video on the prompt-80 is up at https://www.youtube.com/watch?v=C9CFD0suW_0 in case anyone is curious.

It managed to get upgraded and now runs Forth and includes a speech synthesizer :) I entered a short machine language program via the keyboard too, enough to blink the lights. I didn't record using the EPROM programmer in the video, but I had success with that too -- the EPROM programmer is pretty handy for storing programs.

Scott

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