MCU to MCU Firmware update(flash write?)

[CLee.20]

condition 1 : mcu2, mcu3 has bootloader.

Hello everyone.

I understand the basics of IAP, but I do not know how to do IAP between MCU and MCU, so I will leave a question.

Question 1. How to write a random Flash address from MCU1 to MCU2 using SPI communication?

Question 2. Write binary file from MCU1 to SD card of MCU2 using SPI communication

Question 3. How to write to a random Flash address of MCU3 from MCU2 using UART communication?

The above 3 steps plan to communicate using a communication protocol.

[TDK]

You could use the bootloader to write to flash. See:

https://www.st.com/resource/en/application_note/cd00167594-stm32-microcontroller-system-memory-boot-mode-stmicroelectronics.pdf

https://www.st.com/resource/en/application_note/cd00264342-usart-protocol-used-in-the-stm32-bootloader-stmicroelectronics.pdf

https://www.st.com/resource/en/application_note/an4286-spi-protocol-used-in-the-stm32-bootloader-stmicroelectronics.pdf

There's no easy way to write to the SD card of one chip from another chip. You'll need to write your own code to do so. Break it into steps. Get writing to an SD card working, then get communication between chips working, then put them together.