- A KR580WW51A (russian clone of the 8251) is used by Aleste 520EX, clock source comes from a 8253 chip.
- A 8251 is said to be used by Cirkit serial interface, clock source and I/O ports are unknown.
8251 vs 8251A
The original 8251 seems to be very rare (there's no programming info found in the internet). The 8251A is backwards compatible, but includes some additional features. The 8251A gives some details on the additional features, so one could eventually use the 8251A datasheet to reconstruct the functionality of the original 8251.
However, since the 8251 is so rare, it's rather doubtworthy that the Aleste or Circit actually uses that chips, probably they use 8251A chips.
- The Circit advert says 8251 (which is maybe meant to be an abbreviation for 8251A).
- Russian to Western part number translation tables say KR580WW51A is 8251 (probably an abbreviation for 8251A, too) (especially as the ending "A" in "KR580WW51A" implies that it is an 8251A).
Datasheets
- Media:8251A.pdf - newer 8251A datasheet (detailed info)
- Media:8251.pdf - older 8251 datasheet (pin-outs only, without programming info)