Specifications

MCU slave software
Developer’s Serial Bootloader, Rev. 13
Freescale Semiconductor 51
Figure 33. MC68HC908GP bootloader flowchart
8.3.1 FLASH programming routines
The main code is similar to the previous implementation with the calibration phase omitted. The FLASH
programming by the bootloader is shown in Figure 34. Three main subroutines are defined as follows:
• CPY_PRG — copies the selected routine into RAM
RESET
SRSR RESET
SOURCE TEST
MCU CONFIG
ICG, SCI INIT
WAIT FOR COMMAND
SEND IDENT DATA
RECEIVE ADDRESS RECEIVE ADDRESS
RECEIVE LENGTH
RECEIVE DATA
CALL WRITE
ROUTINE IN ROM
CALL ERASE
ROUTINE IN ROM
RECEIVE ADDRESS
RECEIVE LENGTH
SEND DATA
SEND ACK
EXECUTE ILLEGAL
OPERATION
SEND ACK AND
WAIT FOR ANSWER
YES
YES
USER CODE
START
POR CAUSED RESET
IDENT? ERASE? WRITE? READ? QUIT?
YES YES YES
YES
NO NO NO NO
NO
1
2
1
2
2
2
ACK RECEIVED
NO
NOT POR
BEFORE TIMEOUT
COPY WRITE
ROUTINE TO RAM
COPY ERASE
ROUTINE TO RAM