I've selected the SAMD21 and plan to use a serial loader. Destroying the loader would be unfortunate, but if I can't fix it with the tools on hand then another chip will be ready. ;-) --=20 James Cameron http://quozl.netrek.org/ --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .