I have migrated from the Temic T89C51RD2 to the Atmel AT89C51ED2.

FYI:

I also have a batch of chips labelled Atmel 89C51RD2-CM. The Atmel factory people and I were able to confirm that they are actually Temic T89C51RD2 parts.

1. Atmel has never made a -CM part, only -IM
2. The parts actually have the EEPROM memory, confirmed by a quick software update to add a data dump.

It started out as an e-mail from me to Atmel to confirm which of the Errata applied to the parts, as I did not see the lot code listed in the Errata Sheet.

-- Tom Bachmann