To create a dual rom on a 27c4096(512K) ROMthecaver99 wrote: ↑Tue Sep 01, 2020 7:21 pmivw 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
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.