tboot Loader is a ultra small (only 256 bytes) opensource boot loader for AVR microcontrollers, it's used for programming flash using a
serial link between your computer and the microcontroller through any free COM port (or USB to serial adapter).
tboot consists of two parts:
1. on chip boot loader, that resides at the boot section of the flash memory, this loader based on SSBL bootloader
2. windows software, the console utility, that has the responsibility of writing/reading data into/from the microcontroller
Tested on devices:
ATmega8, ATmega8535, ATmega32;
If you used tboot Loader with other devices, please inform me (firstname.lastname@example.org).
Usage: tboot [options] Options: -p <partno> Specify AVR device. -b <baudrate> Override RS-232 baud rate. -C <config-file> Specify location of configuration file. -p <partno> Specify AVR device. -b <baudrate> Override RS-232 baud rate. -C <config-file> Specify location of configuration file. -P <port> Specify connection port. -U <flash|eeprom>:r|w|v:<filename.ext> Memory operation specification. Multiple -U options are allowed, each request is performed in the order specified. -n Do not write anything to the device. -V Do not verify. -v Verbose output. -q Quell progress output.
tboot -U flash:w:data.hex
writes firmware from data.hex file into avr
tboot -U flash:r:data.bin
reads flash memory from avr to data.bin file.
The file expansion should be .hex or .bin for Intel hex or simply binary file format.
Each command is one character, possibly followed by data. Data is sent in hexadecimal, in lowercase. Whitespace or other characters in hex strings sent to SSBL are not allowed and will cause an error. The bootloader responds to unrecognized characters with a '!' char. When waiting for a command, the bootloader sends a CR (ascii 0x0D). The exception to this is the 'p' command, which does not send a CR when it finishes.
In Makefile is necessary to specify the microcontroller name (MCU=atmega8) and the bootloader offset
(BOOTSTART=0x1F00). The bootlaoder offset is equal to device flash size - 0xFF.
In tboot.S need to define constants FOSC and BAUDRATE and to specify an port and pin which will be used for bootloader control (CONTROL_PORT_DDR, CONTROL_PORT_PORT, CONTROL_PORT_PIN, CONTROL_PIN).
Download:Bootloader firmware sources and windows software