I have studied Philips 8051 uC's (P89C668, Rx) and now discovered Atmel's variants which sounds rather interesting. Is AT89S51 to recommend? Or AT89C55?
If you want to go Atmel, use one of the variants with "built in serial ISP" such as the T89C51Rx2 (roughly equivalent to the Philips P89C51Rx2). I, however, after once having to wait for revision 's' before an Atmel circuit worked as it should am an ardent Philips fan.


Erik