Bootloader command set

AN3262

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Doc ID 17845 Rev 2

Figure 18.

3.5

it transmits the ACK byte to the application. After sending the ACK byte, the bootloader waits

for an address (4 bytes, where Byte 1 is the address MSB and Byte 4 is LSB) and a

checksum byte, then it checks the received address. If the address is valid and the

checksum is correct, the bootloader transmits an ACK byte; otherwise, it transmits a NACK

byte and aborts the command.

When the address is valid and the checksum is correct, the bootloader firmware performs

the following:

●

It initializes the registers of the peripherals used by the bootloader to their default reset

values.

●

It initializes the user application's main stack pointer.

●

It jumps to the memory location programmed in the received ‘address + 4’ (which

corresponds to the address of the application's reset handler).

For example, if the received address is 0x0800 0000, the bootloader will jump to the

memory location programmed at address 0x0800 0004.

In general, the host should send the base address where the application to jump to is

programmed.