ST AN3154 Application note

About this manual

This document details the CAN protocol implementation within the STM32 microcontroller bootloader. It outlines the sequence of operations the bootloader follows upon detecting a CAN frame, including checks for the external clock frequency (HSE) before accepting commands.

The note provides a comprehensive list of supported bootloader commands, such as Get Version, Read Memory, Write Memory, and Erase Memory. It also specifies the CAN settings, including support for standard and extended frames, baud rate configuration up to 1 Mbps, and specific identifier and data field requirements for communication between the host and the device.

What's inside

• Bootloader code sequence
• CAN settings
• Bootloader command set
• Device-dependent parameters
• Get command
• Get Version & Read Protection Status
• Get ID command
• Speed command
• Read Memory command
• Write Memory command

Specifications

Frequently asked questions

What is the initial baud rate for the CAN bootloader?

The initial baud rate is 125 kbps, which can be changed via the speed command.

What is the maximum bitrate supported by the STM32 CAN bootloader?

The maximum bitrate supported is 1 Mbit/s.

What happens if the RDP (read protection) option is active?

Only a limited subset of commands is available; all other commands are NACKed and have no effect.

How many data bytes can a single incoming message contain?

Incoming messages can contain from 1 to 8 data bytes.