Part data sheet and CAN bootloader documentation recommend "releasing" PSEN before the end of RESET when using PSEN=0 as the "hardware condition" forcing the on chip CAN bootloader to execute.
The Atmel Demo board just has a DIP switch to ground to force PSEN=0; it doesn't "release". Even though the Demo board doesn't use PSEN as an output, shorting this pin to ground must not be a good idea.
Does anyone have a practical circuit to properly drive and release the PSEN pin? The data sheet is pretty vague about the properties of this pin during the brief time it is an input. How about grounding it through a resistor? value?
Can the on-chip CAN bootloader be used to boot more than one T89C51CC01 on a CAN segment? If not, what is the best way to boot/ISP a bunch of these parts on the same CAN bus segment? They will all get identical code loaded into them.
Paul Smith Indiana University Physics