Introduction

Shortly after the release of the PIC18F family, Microchip released a bootloader compatible with the new devices. There were several attributes that I liked about this bootloader. It was built to fit in the PIC18F boot code block and could be code protected separately from the user code. It also supported a wide range of PIC devices and clock speed, which I hadn't found in other bootloaders. Best of all, it was free!

However, there were some things I didn't find in this bootloader. I wanted the PIC to stay in boot mode after reset for a short time and then jump to user code if the bootloader was not invoked. I also wanted to be able to program new code in one operation (Microchip's bootloader application forced you to first erase the whole code space, then program the chip). Finally, I wanted a way for the bootloader to change Config bits and EEPROM data.

For these reasons, I decided to create the Jolt Bootloader. The Jolt bootloader is a combination of a bootloader application that runs on a PC, Macintosh or Unix workstation and a bootloader firmware that runs on the PIC18 devices.

PIC is a registered trademark of Microchip Technology Inc.