27C400/27C800 EPROM emulator

[cmorley]

Could you let me know a price please?

Yep here is the sales thread. Postage prices have all gone up as of Monday - 8% inflation busting rise, thanks RM - so £2.25 UK 1st class now.

[rubber_jonnie]

Could you let me know a price please?

Yep here is the sales thread. Postage prices have all gone up as of Monday - 8% inflation busting rise, thanks RM - so £2.25 UK 1st class now.

@cmorley Thank you.

[cmorley]

OK... I found some enthusiasm and finished the "no reset wire" firmware.
v0.7 firmware dropbox link

You will need to update the microcontroller and the CPLD firmware.

After upgrading go in to the options and set them as you wish. Don't forget you can use the PRESET wizard to set the module up quickly. Also don't forget to COMMIT the options to FLASH.

ROM switch timings are a bit quicker now.
<1s - ignore
>1s - switch to NEXT ROM
>3s - swithc to ROM zero (optionally quick tap reset n times to go to ROM n)
>5s - no ROM switch

You can connect a (power) LED to the pad next to PIN 1. It is open drain so you connect the other end of the LED to 5v - use a series resistor so the microcontroller pin isn't current limiting.

The ROM switch without using a RESET wire works by monitoring A0. If it sees no change on A0 for a while (>30ms) it assumes the machine is in RESET. I have tested this on an Amiga A500. It might work on other machines (very probably most other 680x0 machines) depends on the CPU behaviour when in reset.

Chris

[cmorley]

Firmware like buses!

v0.8 firmware dropbox link

Improved debounce on ROM switch signal.

I found the wireless ROM switch was unreliable on a different Amiga so I improved the debounce a little.

[cmorley]

v0.8 Firmware works with wireless ROM switching on the 6502 based Acorn Master too :D

No flylead/clip required.

[cmorley]

No complaints about v0.8 firmware problems... does that mean it works for people or no one was brave enough to try it yet? :?

[terriblefire]

I should update and try!

[cmorley]

I've tested the v0.8 firmware in my Amiga A1200 & A600 now.

Works in both but the reset seems a bit delayed (is it debounced?) on an A1200 so you should wait for the LED to go dim then count the seconds to switch ROM.

On A1200 & A600 the board pins are very close to the back metal of the keyboard. Shorter pins (& cropped) and insulation is a must - expecially on the A1200 where the keyboard can flex. Otherwise the keyboard will touch pins 1-20 (there is no Vcc on that side but still don't short the address bus!)

[simon.wilkie]

I've tested the v0.8 firmware in my Amiga A1200 & A600 now.

Works in both but the reset seems a bit delayed (is it debounced?) on an A1200 so you should wait for the LED to go dim then count the seconds to switch ROM.

On A1200 & A600 the board pins are very close to the back metal of the keyboard. Shorter pins (& cropped) and insulation is a must - expecially on the A1200 where the keyboard can flex. Otherwise the keyboard will touch pins 1-20 (there is no Vcc on that side but still don't short the address bus!)

Just checked this on my setup and the pins are NOT close to the rear of the keyboard on a 1200 as long as you have either the hard drive caddy installed or the floppy securing bracket as the keyboard rests on these far above the EPROMS. :dualthumbup:

[terriblefire]

Hi,

Can I ask a silly question? So i have flashed a ROM with EmuTOS in 27C200 mode, 256KB rom, slot 0.Works.

I then flashed slot 1 with DiagROMST.

I then selected slot 1 using "w" in the boot menu. But it always boots EmuTOS. I dont want any external pins to select the rom. just the setting in the menu. Does this work? It always boots EmuTOS even though the browser shows DiagROM code in slot 1.

Sorry if this is obvious. I have the latest firmware updates.

D1EF904D-C7C4-4D43-9AF7-7F6783D442C8.jpeg

This is using @exxos's new decoder and @EzdineG's A1000 rom switcher for crossing the streams fun.