Wanted: ASM-48 for Intellec MDS-2

Eric Smith spacewar at gmail.com
Fri Apr 3 22:57:05 CDT 2015

On Fri, Apr 3, 2015 at 2:30 AM, F.Ulivi <fulivi at tiscali.it> wrote:
> I'm going to use the ASM48 assembler to write a firmware from scratch
> for the PIO (parallel I/O) microcontroller on the IOC board. It's a
> 8041A (ROM masked version) and it's labelled A72 on the schematics.
> By looking at the picture you took of an IOC board it's clearly a masked
> ROM (no UV window). Because of this I think it would be very hard to
> find the ROM image. AFAIK dumping it would require a microphotograph of
> the die and a lot of patience to recover the ROM bits....

I'm 99% certain that the 8041 and 8041A masked ROMs can be read with
essentially the same verification mode as the 8048 and 8048A,

If I recall correctly, for the 8048, ROM verification mode works just
like verification of the EPROM of an 8748, but with 12V on the PROG
pin rather than 25V.  The A-suffix parts have different
programming/verification requirements than the non-A parts, so be

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