Writing RiscOS 3.11 to rom

[nicf82]

I have got an A3000 with broken Roms so would like to write some new ones.

I gather I need to get some 27C040 EPROMS, or is it possible to use EEPROMS?

Also I need to get a writer but would be good to get one that was capable of writing to a range of types of chip, that might be useful for various retro machines, any recommendations?

Cheers!
Nic

[IanS]

27c040 should be fine, or 27c4001, or probably a few others.

I normally use 39sf040 flash chips for other machines, but not really practical on an A3000 as you can't easily re-map pin 1.

I'm not aware of any eeprom that have a suitable pinout, not saying there aren't any, just never looked.

Be aware that the usual downloads that appear to be 4 files for 4 rom chips, they aren't. You need to shuffle the data around a bit - viewtopic.php?p=420351#p420351

[nicf82]

Thanks IanS!

Sounds like the 27c040 or 27c4001 are the ones to go for then. I assume they will work in an A310 (with carrier board) and an A4000/A5000 as well?

I do have one of these lying around, but never used it:

It is only 28 pins so too small for these chips but I wonder if there is any kind of adapter? I think it is for the BBC?

Cheers
Nic

[danielj]

Hi Nic,
You won't get away with using a BBC EPROM programmer for anything more than a 27128 (16kb) - you might manage 32kb at a push. You'll need to look at getting something a bit beefier that runs off a PC - this seems to be the general thing at the moment:
https://www.amazon.co.uk/Programmer-Sup ... 0BLSW7B22/

(You can possibly find it cheaper, and with adapters etc - some might be knock offs, you'll need to do some googling to work out the state of play)

[nicf82]

Thanks danielj

Done a bit of googling for those and can see them at all sorts of prices! I assume they are all slight variations on the same thing. Seems like a bit of a minefield, like you say some more research is needed.

Cheers!
Nic

[Ukwebb]

There are other options... https://www.ebay.co.uk/itm/335322014269

[IanS]

I assume they will work in an A310 (with carrier board) and an A4000/A5000 as well?

A310, A5000 - yes, A4000 - no, it uses 2 16-bit chips.

[nicf82]

There are other options... https://www.ebay.co.uk/itm/335322014269

Yes true, I do have a few machines though and have found 1 broken ROM and 1 suspect so far so I would like to learn to burn my own for that reason.

A310, A5000 - yes, A4000 - no, it uses 2 16-bit chips.

Thats good to know, thanks!

[IanS]

I have got an A3000 with broken Roms so would like to write some new ones.

How did you decide they were broken, rom checksum error from post could still be rotten tracks around the rom area.

[nicf82]

Hi IanS

I was having problems with the existing ROMs till I swapped for some other ones, so now I am a set short. Here is the thread discussing the machine:

https://www.stardot.org.uk/forums/viewt ... 62#p418062

Cheers!
Nic