
AN2662
Bootloader description
Doc ID 14156 Rev 1
Figure 1.
Bootloader selection
BL reset
Configure internal RC mode
0x7F received on
USART2
Yes
No
0x7F received on
USART1
Yes
No
Configure USART1
Configure USART2
Configure USART1 and USART2 pins
Configure CAN2
Configure USB
CAN2_RX pin is low
level
No
Execute
BL_USART_Loop for
USART1
Execute
BL_USART_Loop for
USART2
Yes
Execute
BL_CAN_Loop for
CAN2
USB cable
detection
No
Yes
Reconfigure system
clock to 48 MHz and
USB clock to 48 MHz
Execute DFU boot-
loader using USB
interrupts
HSE = 8 MHz,
14.7456 MHz or
25 MHz
Yes
No
HSE = 8 MHz,
14.7456 MHz or
25 MHz
Yes
No