Bootloader

maikelmeyers · Joined: 19 Jan 2007 Posts: 8

Hi,

some questions: Do I have to use the PGM-Pin (Low voltage Programming) on PIC18 devices, when I want to use a Bootloader? Is this Pin latched on startup or does it have to be high all the time?

Thanks

VanHauser · Joined: 03 Oct 2005 Posts: 88 Location: Ploiesti, Romania

PGM pin has nothing to do with bootloaders. Low voltage programming (LVP) is used for in-circuit programming. Just use the NOLVP fuse to make the PGD/PGC/PGM pins normal I/O pins.

ckielstra · Joined: 18 Mar 2004 Posts: 3680 Location: The Netherlands

The PGM pin is used for in-circuit-programmers with only a single power supply, 99% of the programmers are called 'high voltage' and don't need this pin.

As VanHauser said, this pin is not related to bootloaders. Best is to always set the NOLVP fuse which makes this pin available for normal i/o, not doing so could cause problems when a voltage spike on this pin starts programming mode.