"with limited resourses such as found in 8052 systems its all too easy to get carried away with comms stacks which tie up the processor. It is better to do as much as possible at the physical layer(CRC,error correction etc and so on) in hardware"

Sounds like a job for a Triscend E5: physical layer in the programmable logic; higher layers in the 8032!

BTW: The FastChip design software comes with HDLC and DES implementations in hardware (well, the sort of "soft" hardware you get with programmable logic...); I keep thinking that CRCs should be a doddle, but haven't actually got around to trying it yet!