AN3320

Boot configuration

Doc ID 18267 Rev 2

17/29

3.3

Embedded boot loader mode

The Embedded boot loader mode is used to reprogram the Flash memory using one of the

available serial USART1(PA9/PA10), USART3(PB10/11 & PC10/11), CAN2(PB5/13) or USB

OTG FS(PA11/12) in Device mode (DFU: device firmware upgrade).

The USART peripheral operates with the internal 16 MHz oscillator (HSI). The CAN and

USB OTG FS, however, can only function if an external clock (HSE) multiple of 1 MHz

(between 4 and 26 MHz)is present.

This embedded boot loader is located in the System memory and is programmed by ST

during production.

For additional information, refer to AN2606.