Wanted: another 12C for reverse-engineering (two-chip, non-diaper)

[brouhaha]

(11-16-2022 05:15 PM)Mark H. Shin Wrote:  Just out of curiosity , I went ahead and opened it up...

Thanks for sharing the photo. That's definitely the right thing.

I believe the 1LM2 CPU and 1LH1 R2D2 to be cost reductions from the 1LF5 CPU and 1LE2 R2D2 in the earliest Voyager calculators. This was probably migration from an older to a newer CMOS process with finer geometry. I haven't seen any official information, though. The progression seems to have been:

1LF5 CPU, 1LE2 R2D2
1LM2 CPU, 1LH1 R2D2
1LQ9 SST
1RR2 SST
2AF1 SST

The 15C always has an additional R2D2 in a square QFP with the LCD driver not bonded out. I've only seen 1LH1-0302 for that, but it is possible that there may have been a version with the 1LE2 (suffix unknown).

I think the 1RR2 or 2AF1 were only used in the 12C, after the other Voyager models were discontinued.