Hello Eric, Me is also very interrested in your tune of "load RTCC". I'm busy to adapt those routines so I can use it with the CCS C-compiler. The CSS C-compiler has also it's own RS232 routine but ofcourse NOT interrupt driven :-( Can you give me a hint how to read the attachment? I may be a stupid question, but i can't make anything out of it? Edwin. Edwin Baaij (Electronic Engineer) ********************************************************************* University of Amsterdam phone: +31-20-5256346 Van der Waals,- ZeemanInstitute fax: +31-20-5255877 Valckenierstraat 65-67 e-mail: baaij@phys.uva.nl 1018 XE Amsterdam *********************************************************************