27C400/27C800 EPROM emulator

[BennehBoy]

Sorry for a thread resurrection!

Thought it may be useful for any other linux users to know that they can get this device to automatically map as a tty device by adding a udev rule similar to the following:

SUBSYSTEMS=="usb", ATTRS{idVendor}=="0483", ATTRS{idProduct}=="5740", GROUP="users", MODE="0666"

[terriblefire]

I recall trying to get this device setup in a way i could switch between DiagROM and AmigaOS for the Amiga 4000 and i couldnt get it to work. It was like the first half of the ROM worked fine but the second was trash. Its a shame because i really wanted to have something like this but it didnt work for me. I assume its just me as others seem to have had OK results.

[BennehBoy]

I recall trying to get this device setup in a way i could switch between DiagROM and AmigaOS for the Amiga 4000 and i couldnt get it to work. It was like the first half of the ROM worked fine but the second was trash. Its a shame because i really wanted to have something like this but it didnt work for me. I assume its just me as others seem to have had OK results.

I've only used mine in my A500, I have a spare 2nd sat about... I was thinking of burning an EPPROM for the 500 and moving both into my A1200 as I've just bought a 1232, but if there're problems with dual roms....

[terriblefire]

I've only used mine in my A500, I have a spare 2nd sat about... I was thinking of burning an EPPROM for the 500 and moving both into my A1200 as I've just bought a 1232, but if there're problems with dual roms....

I honestly dont know whats up. It may be me being an idiot but i could never get it to work reliably.

[BennehBoy]

I'll have a fiddle and report back.

[BennehBoy]

This may be of interest -> https://github.com/cdhooper/kicksmash32

[cmorley]

I think a couple of modules might have had faulty vias to the front pads or cracked later - perhaps I was too racey for the JLC 4 layer process in my via and trace widths in the layout. Most people got them working in 32 bit mode who asked for support - they'd not followed the instructions precisely or assumed some function instead of reading the docs. This is the main reason I didn't continue the project - lots of people don't read docs and the modules weren't intuitive enough to use without docs for some... so they were a support nightmare.

Maybe I'll do another version in the future but I'm too busy with the day job to do any retro stuff at the moment. Emulating a MSC device RPi Pico style might be a better interface... ditch the CPLD and make it robust to people inserting it backwards or 1 pin out. I just don't have the time though sadly.

[BennehBoy]

Hi, the above post was simply in lieu of these no longer being available. Certainly can understand the support nightmare though, PEBCAC!

[dalek]

If you do another batch could I suggest changing the smd pads for extra signals like reset in to through holes?

I stupidly forgot reset was connected and ripped the pad right off when removing mine for programming... users are so dumb

[cmorley]

If you do another batch could I suggest changing the smd pads for extra signals like reset in to through holes?

I stupidly forgot reset was connected and ripped the pad right off when removing mine for programming... users are so dumb

That just wasn't possible, the PCB is too busy. In the following image you can see that the chips on the bottom overlap the top pads.

Screenshot 2024-07-12 134337.png (211.27 KiB) Viewed 1832 times