Motorola 6800 EXORciser development system simulator

by jhallenworld • 3 years ago

30 11 3 years ago

When I was in Uni in the early 90s I used a ICE dev system to write code for the 6809. ICE stands for "in circuit emulator". So you could create a prototype board and connect the ICE to where the CPU was meant to go and then step through any code it needed to run, seeing all the registers on the ICE.

The dev system was a dual M68000 computer running Unix. I don't know what the machine was called.

jhallenworld2• 3 years ago

I used one of these back in the day for 6809:

https://www.iobium.com/applied_microsystems_em189_e.htm

It was awesome. The trace-back memory was great for finding bugs: it would print disassembled instructions prior to some trigger (you could connect the ICE to a terminal to see this).

ajxs3• 3 years ago

Very cool! I've been doing a lot of work reverse-engineering the firmware from Yamaha's 1980s synthesisers[0], all of which feature Hitachi 6303-series processors. The 6303 is Hitachi's second-source implementation of the Motorola 6803 architecture. I'd love to know how these devices were developed. I'm guessing a development platform like this would have been used by Yamaha. If anyone has any more information regarding development targeting the Hitachi 6300 series chips in the 1970s/1980s, I'd love to know!

[0] In case anyone is curious, my latest successful work is hacking the Yamaha DX9 to have the full DX7 feature set: https://github.com/ajxs/yamaha_dx97

Gordonjcp2• 3 years ago

Most likely a "ROM emulator" that would plug into the ROM socket on the board, replacing it with a few kB of static RAM that you can pop stuff into from a computer.

In the mid-90s I used an already pretty obsolete CP/M machine to drive one of those for developing Z80 embedded code. Although PCs were around - 386s and even early 486s if you had the money, they offered no real advantage because the editor, assembler, and linker only took about a second to load from floppy anyway.

Given how much time I spend looking at 80x25 terminals I wonder why I put up with 20-second boot times now, over 30 years later.

ajxs3• 3 years ago

I actually used one of these things[0] during development of the DX9/7 firmware mod. I like your Mirage tools by the way! I've actually got a very battered Ensoniq Mirage I picked up for free that's badly in need of some maintenance. If I can get that running I'd love to give your firmware a try!

[0] https://mygeekyhobby.com/2020/07/05/eprom-emulator/

jacquesm2• 3 years ago

Hey Anthony, nice to see you're still at it!

I really should get that chip to Ken... my todo lists have a habit of getting longer and longer...

ajxs3• 3 years ago

Hi Jacques! That would be awesome. I've seen the inside of quite a few DX7s and DX9s now, but I still haven't come across a ceramic EGS chip yet. I've seen photos, so I know they exist. They must be super rare though.

koz1000• 3 years ago

The EXORciser was also used by Williams Electronics to develop software for pinball machines in the 1980s, as well as the Defender video game.

Here's Steve Ritchie and Larry DeMar working on Black Knight:

https://64.media.tumblr.com/04e09410654d43180fcf2dd0591bba38...

jhallenworld2• 3 years ago

Very cool! I'm going to add this photo to the GitHub readme unless anyone objects.

Motorola 6800 EXORciser development system simulator

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