STMicroelectronics AN3968 STM32F407/F417 IAP over Ethernet Application Note

About this manual

This document provides implementation solutions for In-Application Programming (IAP) on the STM32F407/STM32F417 microcontroller family. It details how to upgrade firmware in the field using the MCU's Ethernet communications interface via two methods: TFTP and HTTP.

The note explains that both solutions run on top of the LwIP TCP/IP stack (v1.3.2). The TFTP method uses a client/server architecture over UDP, while the HTTP method utilizes HTML Forms for file uploads over TCP. It covers the theory of operation, specific implementation steps for each protocol, and software usage instructions.

What's inside

• IAP Overview
• Theory of Operation
• Implementing IAP using TFTP
• TFTP Packet Format
• Implementing IAP using HTTP
• MAC and IP Address Settings
• Jumper Settings on Evaluation Board
• Building an Image for IAP

Specifications

Frequently asked questions

What is the purpose of the IAP code in Flash memory?

The IAP code allows the microcontroller to be put into a mode where it executes firmware upgrade instructions instead of normal application code.

What is the fixed size for data blocks during a TFTP transfer?

In this implementation, the data block size is fixed to 512 bytes.

Which protocols are supported for implementing IAP over Ethernet?

The application note provides solutions using TFTP and HTTP on top of the LwIP TCP/IP stack.

What happens to the user Flash area before new data is written?

The server erases the total user Flash area when a write request is received.