Flash Rom / Kickstart Switcher

[Elmo Putney]

I've been looking for a flash based kickstart solution for my A1200 that exploits the fact that A1200 rom images are only 256k per chip and therefore you can get 2 kickstarts in a (pair) of 512k roms...or 4 in a 1 Meg rom.

Nothing I found on git hub or retail quite fits the bill so I set out to create my own, I have not ordered boards yet but I am close, but just wanted to gauge intertest if I have to order more than I need. Not looking to profit, just recover costs so I would guess £20 per tested board (2X for A1200).

General premise is......

Uses a modern(ish) 29F800 (1M) flash chip = 4 roms on a A1200, 2 on a A600/A500

Can use a 29F200 (2M) flash = 4 roms on a A500 (8 on an A1200 but why?)

Jumpers on board for config, but I have not included pre rev 5 A500 fixes.

I'll share pcb layout/gerbers happily.

[alexh]

https://www.exxosforum.co.uk/forum/v...hp?f=63&t=4261
http://www.boobip.com/hardware/27C400_EMU
[ Show youtube player ]

https://www.amiga-shop.net/en/Amiga-...tor::1305.html

[Elmo Putney]

I'm aware of most of those, the boobip looks great but the chips used are unobtainium. I did contact him but no plans to make any.

Also most boards do not break out A17 e.g.

Which means you can not take advantage of A1200/A400 (&3000?) dual kickstart Roms only needing 256k in each rom.

[AJCopland]

Nice, can you use this to store a larger rom as well so we build our own of 256, 512, or 1MB in size?

[alexh]

Originally Posted by Elmo Putney

Which means you can not take advantage of A1200/A4000 (&3000?) dual kickstart Roms only needing 256k in each rom.

I think that is because of the popularity of custom 1MB ROMs. If you disconnect A17 from the socket and drive it from a JUMPER then you restrict yourself to 512KB ROMs

[Elmo Putney]

The way I have routed the board there are jumpers to either route A17/A18 (and A19 if using a 2Mbit Rom) to a selection switch or to the socket so you can choose to have big roms or multiple roms.

Using a 29F200 (2Mbit) - you could have 4 big roms switchable.

[AJCopland]

Oh cool

[alexh]

I'd be interested, especially if they can be programmed in-situ

[Elmo Putney]

Originally Posted by alexh

I'd be interested, especially if they can be programmed in-situ

Thats too much for me, if there is an open source design out there that does this then I'll happily mod / re-mix, but I've not found one.