Bootloder for AVR After powering up of AVR - MCU waits for the data from ARM. While "$" received, AVR strats to receive packets which consit of ############################################## # $ + Packet # + Size of packet + CRC + Data # ############################################## When received, AVR calculates CRC of Data just by sum of all bytes of Data.If CRC equals the received CRC in Packet Header then AVR sends to UART number of received packet, that means that packet received correctly and we can receive the next packet. MAIN RESTRICTION - allow to send only 99 of packets. So the hex file shouldn't be more then 12627 bytes if more, program need to be changed. WHAT IS GOING 2 B IMPLEMENTED LED indication of each packet Watchdog if nothing is going on Check every 128 bytes received, and write in flash if the content is different LED indication of succesfully received firmware Led indication for waiting time for incoming firmware Algorithm for flashing firmware WHAT IS ALREADY IMPLEMENTED AND CHECKED