bootloader and fuses

[Christophe]

Hello,

a simple question.

You have a bootloader program which has as fuse:

[Rohit de Sa]

A bootloader is a program that resides in the microcontroller's memory. It is called upon only when there is need to reprogram or modify the user code on the microcontroller. As far as my experience goes, I have never seen configuration fuses being modified by user code; ie once the bootloader is burnt, you can't touch config fuses - and this sort of makes sense - suppose the bootloader changes the oscillator type while reprogramming it may not be possible to continue programming!

So a short answer - yes, your main program will use the internal oscillator. , And for that matter, it can ONLY use the internal oscillator and nothing else.

Rohit

[ckielstra]

It depends on the bootloader. As Rohit already mentioned, most bootloaders don't support changing the fuses. There are however a few exceptions where it is desired to change the fuses, for example to activate the read protection fuse. Most PIC processors allow the user program (or bootloader) to activate this fuse, but it works only in one direction. Once activated (the bit is set or reset, I don't remember) you can only reverse the setting by doing an 'erase-all'.

In short: uploading a user program without fuse settings will use the original bootloader settings.
If the user program does contain fuses, the result will depend on the capabilities of the bootloader and the fuses.

[asmallri]

[Christophe]

Okay, thanks everybody. I need to change the bootloader fuses then.