Hello! This is my first post here so please be kind.. :-D I'm working on a 18F452 with MP Lab 6 C compiler and a ICD-U40 programmer. I'm experiencing a weird problem, I try to explain it as much clear as I can :-)) My sample program is very simple, it just outputs alphabet letters (A -> Z and repeat) on a 9600 bps software UART using MPLAB-provided libraries, in an infinte loop. It would works correctly but after about 3 seconds of starts the PIC seems to auto-reset itselfs, and it goes on autoresetting every 3 secs. (just to be sure, I also toggle a led in main() and it confirms this autoresets) Reading RCON register just after main() and on every reset (but before to setting it to 0x1f for clear) reports 23 decimal as previous startup cause. If I'm right it should be WatchDog Timeout. But I don't understand why... further, I also tried disabling WD in config-words (_and_ setting WDTCONbits.SWDTEN=0) but nothing changes. Idem modifying WD prescaler, no-change :( Someone could, please, enlight me ? What I miss ? Where am I wrong ? Many thanks in advance!! -- bye! Ale ale@unixmania.net -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.