AN2430 Datasheet, PDF (8/24 Pages) STMicroelectronics – STR75x SystemMemory boot mode

General description
AN2430
1.4.4
Write Memory command
Description:
This command allows the user to write data to any address memory (RAM, Flash or
registers).
When the bootloader receives the Write Memory command, it transmits to the user the ACK
byte.
After the transmission of the ACK byte, the bootloader waits for an address (4 bytes, byte 1
is the MSB and byte 4 is LSB of the address), checks this address, if the address is valid, it
transmits an ACK byte otherwise it returns a NACK byte (0x3F) and exits from the
command.
When the address is valid, the bootloader:
● Gets a byte which describes the amount of data to be received (N bytes),
● Receives the user data ((N + 1) bytes),
● Programs the user data to memory starting from the received address,
Finally, at the end of the command, the bootloader transmits the ACK byte if the write
operation is completed successfully otherwise a NACK byte (0x3F) is returned and the
command is exited.
8/24