CCS bootloader overwrites himself?

dirk · Guest

Hi,
I have a problem with the ccs-bootloader, I use it with a PIC18F252.
I made the required changes and tried the example bootload.c.
Everything works fine.
Now I need to load my own application in the PIC.
After re-boot the complete Code in the PIC is destroyed.
The application doesn`t run, re-booting and bootloading again is not possible.

In the application-code is no #org-directive,
but a #rom-directive to store data in internal EEPORM.

After reading the PIC with a Programmer I recogniced, that parts of the application are written in Memory at adresses lower then 0xf500.

So I think the bootloader has been overwritten.

Can anywhone help me?

Many Thanks

Dirk

Ttelmah · Guest

You need to use the #build directive in the application, to make it load above the bootloader.

Best Wishes

SherpaDoug · Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA

There are bits and pieces all over this forum, but is there anywhere a good explaination of how to use a bootloader, including what changes have to be made to stand-alone code to make it bootloader compatible, and what you need on the PC end? I have been using PICs for almost 20 years but I have never had to use a bootloader until now.
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grasspuddle · Joined: 15 Jun 2006 Posts: 66

the ccs bootloader uses 0-500 (hex) for the bootloader. look at your program code you want to load. that data range should be empty and the beginning of your code should start around 501

SherpaDoug · Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA

Unfortunately the bootloader I have to use is a derivative of the CCS one that uses RS485 with Ethernet style packets designed for sending sensor data. It is largely undocumented and takes 2176 bytes of ROM. Maybe I should learn how to use the simple CCS one first.
_________________
The search for better is endless. Instead simply find very good and get the job done.

dirk · Guest

Many Thanks for your Help,
I thought the bootloader adds an offset to the application-programm.
Now I have included the bootloader.h-file and everything works fine.

Best Wishes

Dirk