DocID022782 Rev 2

5/16

AN4045

IAP overview

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1

IAP overview

The devices of the STM32F3 series, also named STM32F3xx in this document, are

implemented in the STMicroelectronics evaluation boards.

1.1

Principle

Users have to program the IAP driver to the Flash memory base address via the JTAG/SWD

interface using the chosen development toolchain or the factory-embedded boot loader in

the System memory area.

The IAP driver uses the USART to:

•

Download a binary file from the HyperTerminal to the STM32F3xx internal Flash

memory.

•

Upload the STM32F3xx internal Flash memory content (starting from the defined user

application address) into a binary file.

•

Execute the user program.

1.2

IAP driver description

The IAP driver contains the following set of source files:

•

main.c: where the USART initialization and RCC configuration are set. A main menu is

then executed from the menu.c file.

•

menu.c: contains the main menu routine. The main menu gives the options of

downloading a new binary file, uploading internal Flash memory, executing the binary

file already loaded and disabling the write protection of the pages where the user loads

his binary file (if they are write-protected).

•

flash_if.c contains write, erase and disable write protection of the internal Flash

memory.

•

common.c: contains functions related to read/write from/to USART peripheral

•

ymodem.c: It is used to receive/send the data from/to the HyperTerminal application

the file” error message is displayed. If the data is received successfully, it is

programmed into the internal Flash memory from the appropriate address. A

comparison between internal RAM contents and internal Flash memory contents is

performed to check the data integrity. If there is any data discrepancy, the “Verification

failed” error message is displayed. Other error messages are also displayed when the

image file size is greater than the allowed memory space and when the user aborts the

task.

•

STM32F3xx Standard Peripherals Library.

a. The Ymodem protocol sends data in 1024-byte blocks. An error check is performed in data blocks transmitted

to the STM32F3xx internal RAM to compare the transmitted and received data. Blocks unsuccessfully received

are acknowledged with an NAK (Negative Acknowledgment). For more details about the Ymodem protocol,

refer to existing documentation.