EXXOS IDE V1.1 R1C BUILD & INSTALL INFORMATION

[rubber_jonnie]

ivw ordered one of the bare boards just out of curiosity where would i get the image for the 27c4096 eprom or is it a matter of loading 1 image in low and other in hi space and is there anything i need to do to the roms?
looking forward to building and installing it into my stfm once i get it fixed

To create a dual rom on a 27c4096(512K) ROM

1. Load an image into a hex editor. If its length is not 0x40000(256k, 262144 bytes) pad it out so it ends at 0x3FFFF (256K, 262143 bytes)
2. Append second image starting at 0x40000 and if not 256K i.e.192KB, pad out to 0x7FFFF (512k, 524287 bytes) in other words the end of address space.

You can then burn the dual image to your ROM.

There are however caveats. You might find that your programmer needs to have the image byteswapped before burning. In my particular scenario I use a TL866 II Pro programmer and HexEd (HxD) under Windows and I don't byteswap.

But different combinations require that you do byteswap.

If you get it wrong and program a 27C4096 that cannot be erased (OTP, One Time Programming), then all you can do is chuck the ROM in the bin.

To that end I'd advise that you get 1 or two erasable ROMs so that you can test your images before you commit to an OTP ROM.

[thecaver99]

i have a gq-4x rev 1 programmer which ive had for years and been a good programmer, i have the 16 bit adapter for these eproms.
how would i know if i need to byte-swap the rom when i load it into software.
what would a sutable rewritable eprom be for this which is an equivelent to the 27c4096?

[rubber_jonnie]

i have a gq-4x rev 1 programmer which ive had for years and been a good programmer, i have the 16 bit adapter for these eproms.
how would i know if i need to byte-swap the rom when i load it into software.
what would a sutable rewritable eprom be for this which is an equivelent to the 27c4096?

It seems to be dependent on programmer, though I can only say in relation to my TL866II Pro, which doesn't seem to require byte-swapping.

I got my last bunch of 5 UV eraseable 27C4096 chips from eBay. They took a while to come but are all good, though already used components. Given that new OTP ROMs are in the region of £5 each, I won't take the risk that I have it wrong any more.

You may also be able to find EEPROM versions of the 27c4096, though I haven't managed to yet, and at least the UV erasable type are very easy to ID.

[thecaver99]

I've ordered an new TL866II Pro as the gq-4x is playing up now as its very old so will use that to flash the eprom when it arrives

[thecaver99]

ive got the TL866ii with plcc adapter but wont reconise the adapter when i have the eprom in it as winges about the pins ahh

[troed]

ive got the TL866ii with plcc adapter but wont reconise the adapter when i have the eprom in it as winges about the pins ahh

Is it this issue?

https://blog.troed.se/2020/07/22/plcc-4 ... ith-tl866/

dip40plcc44_2.png

img_2739.jpg

[rubber_jonnie]

Very likely, the adapter that came with my TL866 had this problem too. I've been told it's because the adapters are wired for microcontrollers not ROMs. Easy to fix.

[thecaver99]

thank you, i can do this mod after work today and see if it works

[thecaver99]

of forgot to ask is it just connecting the 2 pins on either side or is there track to cut as well bit difficult to see in pic butwill give it a go

[troed]

of forgot to ask is it just connecting the 2 pins on either side or is there track to cut as well bit difficult to see in pic butwill give it a go

If it's the same issue then you just need to connect the pins on either side - nothing to cut. I hope my blog entry explains the details.

/Troed