>have just found out that 18F252 and 452 seem to be or >become obsolete and replaced by 2520 and 4520 Yeah, that is why I specifically put in something about "later versions" - I knew they were now regarded as "not for new designs" or something along those lines. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist