27C400 EPROM emulators (beta) issue D technical discussion

General discussions or ideas about hardware.
cmorley
Posts: 291
Joined: Tue May 28, 2019 5:46 pm

Re: 27C400 EPROM emulators (beta) issue D technical discussion

Post by cmorley »

Please update the thread if you hear further news. I'd be interested to find out why it doesn't work in your setup. :)
nivrig
Posts: 16
Joined: Mon Jul 26, 2021 3:42 pm

Re: 27C400 EPROM emulators (beta) issue D technical discussion

Post by nivrig »

lukzer has started looking at the issue now.

He asks, what are the latest firmware versions for the emulator?
cmorley
Posts: 291
Joined: Tue May 28, 2019 5:46 pm

Re: 27C400 EPROM emulators (beta) issue D technical discussion

Post by cmorley »

All issue D modules shipped with the same final firmware. There are no updates.
nivrig
Posts: 16
Joined: Mon Jul 26, 2021 3:42 pm

Re: 27C400 EPROM emulators (beta) issue D technical discussion

Post by nivrig »

Update, for the record, here because the thread was split. Looks like the 5719 GARY chip in this A500 was faulty. A replacement GARY got the accelerator and emulator working together.
BennehBoy
Posts: 219
Joined: Sat Apr 24, 2021 12:35 pm

Re: 27C400 EPROM emulators (beta) issue D technical discussion

Post by BennehBoy »

Apols for the thread resurrection!

There's been mention of using these in 8bit machines, I'm quite interested in trying to get one of mine working in a c64, I have a desire to be able to easily switch between ~ 16 kernels, and rather than come up with some hackery using a 27c020 & an Arduino/stm32, this seemed like a possibility.

Would I need to have some switching in the interface layer because there's no 64kbit rom size option (32kbit 16 bit?), I guess there would need to be some firmware changes to get to that level of granularity within the emulator, and from what I had seen there wasn't much flash space left on the atmel.

Just curious as I really like how simply the switching works, and it would be simply to hook the restore key up to the rom switch line in a 64 (since there's no reset switch on a standard machine).
cmorley
Posts: 291
Joined: Tue May 28, 2019 5:46 pm

Re: 27C400 EPROM emulators (beta) issue D technical discussion

Post by cmorley »

The STM32 ran out of pins so 27C200 is the smallest. You could put a switch on A16 and get 2x banks per ROM switcher bank if you must have more than 8x images... you can put it in 8-bit more with the /byte pin (just the same as a 27c400).
BennehBoy
Posts: 219
Joined: Sat Apr 24, 2021 12:35 pm

Re: 27C400 EPROM emulators (beta) issue D technical discussion

Post by BennehBoy »

OK, thought as much (not sure why I wrote atmel above though, age!), thanks for taking the time to respond.
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