InventorPatentor
Newbie level 5
I am (with help) developing a USB product based around PIC18F3K50 (which supports ss-ICSP). For programming it, instead of adding a special ICSP adapter to my PCB, I’d like to use the existing USB plug somehow. Of course, the PIC can’t simply be programmed over the pins used for USB communication, but there might still be a way to make use of the USB plug for programming!
For ICSP, the following PIC pins are involved:
VPP (not needed for ss-ICSP)
VDD (already wired to VBUS of USB plug)
GND (already wired to GND of USB plug)
PGD (already wired to D+ of USB plug)
PGC (already wired to D- of USB plug)
PGM (should be enabled for ss-ICSP)
My idea was to wire PGM (or VPP, in case high-voltage ICSP programming is better) to the USB shield! Of course, the product would not conform to the USB standard during firmware programming, and I would have to use a non-standard connection on my USB ICSP programming adapter - but that is no big issue, because my product is only going to be firmware-programmed on the factory, not on the field. However, the product must of course work normally after the firmware programming is completed.
Ideas, feedback, suggestions?
For ICSP, the following PIC pins are involved:
VPP (not needed for ss-ICSP)
VDD (already wired to VBUS of USB plug)
GND (already wired to GND of USB plug)
PGD (already wired to D+ of USB plug)
PGC (already wired to D- of USB plug)
PGM (should be enabled for ss-ICSP)
My idea was to wire PGM (or VPP, in case high-voltage ICSP programming is better) to the USB shield! Of course, the product would not conform to the USB standard during firmware programming, and I would have to use a non-standard connection on my USB ICSP programming adapter - but that is no big issue, because my product is only going to be firmware-programmed on the factory, not on the field. However, the product must of course work normally after the firmware programming is completed.
Ideas, feedback, suggestions?