After a few seconds - viola - the new user program is running in the PIC. The bootloader and PIC downloader shake hands and then the hex-file is downloaded.
MICROCHIP PIC BOOTLOADER SERIAL
The reset activates the bootloader and makes it listen for a new download on the serial port. Load the hex-file into the PIC downloader (click Search or press F2), activate the downloader (click Write or press F4) and reset the PIC. The PIC downloader writing to the target PIC A test program is also included in the bootloader software package.įig. An UART test program for 16F873 and a description of a testboard for 16F873 can be found elsewhere on this site. After having programmed the bootloader into the PIC, the download procedure is tested by downloading a suitable program into the PIC. The PIC downloader is used for transferring the hex-file from your PC to the bootloader in the target chip. This is because the bootloader does not change the configuration word of the PIC.Ī PIC downloader is contained in the bootloader software package. The fuses selected when programming the bootloader can not be changed later by the downloaded user program. Fuse settings for programming the bootloader My recommended fuse settings are shown in figure 2.įig. If the Low Voltage programming fuse is on, the PIC may become unstable during operation. I did not want the Low Voltage programming to be on (which it is in the hex-file). Load the hex-file into the PIC-programmer and check the fuse settings before programming.
MICROCHIP PIC BOOTLOADER HOW TO
I'll explain the procedure by giving an example how to program the bootloader version 8.23 into a 16F873.Ĭhoose the hex-file with the right crystal oscillator frequency and the desired download speed. The bootloader package contains all the software needed. If no download is detected, the bootloader activates the user program, starting with the first 4 reallocated words and then jumping to the remaining user program. At boot time, the bootloader waits 200 ms for a download to begin.
The original 4 words are recognized during download and reallocated to the memory space of the bootloader. The first 4 words in the flash memory (0x000 to 0x003) contain a jump to the bootloader.
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