Mystery chip SCM44506L
Brent Hilpert
bhilpert at shaw.ca
Thu Oct 10 12:22:58 CDT 2019
On 2019-Oct-10, at 5:33 AM, Wouter de Waal via cctech wrote:
>> Very likely a semi custom or custom memory device, due to the prefix.
>
> Armed with that and the fact that pin 1 connects to the leadframe I figured maybe it's something like the 6830 Mikbug prom -- 0V on 1, 5V on 12, data on the left, address on the right. Tried reading it like that (for all 16 combinations of chip selects) but 0xFF throughout.
>
> So I popped the lid, stuck it under a microscope. The chip says "MCM6816" which is in fact a 1k ROM.
>
> Anyone have more information on the 6816 ROM?
Funny, the usual goto reference for early 6800-series chips is the 6800 Micro System Design manual:
http://bitsavers.org/components/motorola/6800/MC6800_Microcomputer_System_Design_Data_1976.pdf
but it's not in there.
There are a couple of other 1K ROMs however (6830,68308).
Might compare pinout with those.
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