On Jun 27, 8:13, <pzachary(a)sasquatch.com> wrote: portable? If you mean file format, probably Intel HEX files. I usually use binary for ROM images, but those ROMs are small so it's not really an issue. More programmers handle Intel HEX than S-records (though some handle both, and there are various utilities on the net, including mine, to convert between them). If you mean data layout in the file, remember those ROMs are 4-bit wide. A lot of programmers only use one half of each byte in the file. Mine happens to use the lower 4 bits, but I believe some may use the upper 4 bits. It might be worth copying whichever 4 bits your programmer provides into the other four (ie if the data in one 4-bit word is binary 1011, and the programmer creates a file with byte value 00001011 for that word, turn it into 10111011). You'll end up with a file that's 512x8 instead of 512x4, of course, but you would anyway, as that's what most programmers use for such devices. -- Pete Peter Turnbull Network Manager University of York