PIC 18F452 Bootloader

Version info:
0.3 11.11.2002	Added support for whole 18Fxx8 and 18Fxx2
		family. Been proven to work on 18F248, do
		not know if other work.

0.2 05.11.2002  Fixed CCS hex file bug and added some
		more hex files to zipfile.
0.1 31.10.2002	Initial and buggy version.

PROBLEMS WITH CORRUPT BOOTLOADER
There seems to be some bugs in the code somewhere,
so the bootloader sometimes gets overwritten. I 
dont have time to fix this now, but an easy workaround
is not to use addres 0x0004 and 0x0006 in the program
memory. In PCH (CCS compiler), include these lines:

#int_global	
void dummy() {}

This is only necessary if you dont use interrupts. If
your program uses interrupt, no modification is done.
(This should do the same thing: #org 0x0004, 0x0008 {},
but I couldnt get that to work (compiler bug?).

DESCRIPTION
Bootloader and downloader based on the famous 16F87x 
bootloader originaly from HiTech. Downloader is rewritten 
to support both 16 and 18 series. The same downloader 
can then be used for both series. Current bootloader 
source does only support 18F452, but it should work on 
other versions of the 18 series with minor changes in the 
source. Both the bootloader and downloader is prepared 
for program memory wider than 16 bit. Current version 
does not support writes to data eeprom.

The downloader is a modified version of the Petr 
Kolomaznik downloader. The bootloader is a modified 
version of his bootloader. Some ideas and code are taken 
from John B. Peatman's QwikBug program, and his QwikFlash 
development board was used during development.


How to use:
Open project in MPLAB and check the .asm file. Set your desired 
settings and remake project. Pin mode and watchdog enabled has 
not been tested, but should work. Provided hex files are assembled
for 18f452 with Time trigger (1 sec), no watchdog, no PLL. (40Mhz 
with PLL). Remember to no use program memory below 0x7D34 in your
user program when using 32kB device, and not below 0x3D34 when 
using 16kB device.


Links:

http://www.johnsrud.no/pic/ - homepage of pic18 bootlo