On Wed, Nov 26, 2008 at 6:08 AM, Steve Smith wrote: > I have just had one of those eureka moments... Not yet tried but planned > > If the RC osc trim constant is overwritten each time you program it for > debug then its internal osc will be 'out' this may be the problem with it > not entering debug properly > That is possible. You still need to check the help file for the limitation with 12F675/12F629. Then you will find the limitation is so great that ICD 2 is less useful for them. For example, this is one of the limitations. "Devices cannot be programmed or read while GP1/RA1 is high (Vih). Move circuitry that makes GP1/RA1 high to another I/O pin during development". This is another one. ICDWarn0033: You have selected Internal MCLR and Internal Oscillator in your configuration settings. If your code makes use of port pins that correspond to Clock and Data pins in programming mode, you may not be able to reprogram your device. See on-line help for this warning for more information. (OK/Cancel) Xiaofan -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist