Pinouts: STM32F429IGT6 to B-U585I-IOT02A

VLaPo.1 · ‎2022-06-21

I'm looking to connect a Waveshare e-Paper display to my STM32U5 discovery kit (B-U585I-IOT02A).

On the Waveshare website (https://www.waveshare.com/wiki/7.8inch_e-Paper_HAT), they have a pinout for the SPI bus on a STM32F4 chip as follows:

Connect to STM32F429IGT6 (SPI)

IT8951 STM32 Description

5V 5V 5V Power input

GND GND Ground

MISO PE13 Data output

MOSI PE14 Data input

SCK PE12 Clock input

CS PE11 Chip select (Low active)

RST PC5 Reset (Low for reset)

HRDY PA7 BUSY state output (Low for busy)

What are the equivalent pinouts for the STM32U585? 5V/Gnd are obvious. I think MISO/MOSI/SCK/CS go to PE12/PE13/PE14/PE15. Perhaps HRDY goes to PA8, but I'm not fully sure. I don't know where RST(PC5) maps to on the STM32U585. Can you please help me?

Also, if I wanted to bypass this RPi HAT, what would you recommend?

Thanks,

Vince

Aime · ‎2022-06-22

Hello @VLaPo.1 ,

Thank you for sharing your question.

It's not that easy to migrate from a STM32F4 to a STM32U5, they are not from the same product's family.

The STM32F4 is a High Performance microcontroller with a embedded Cortex M4 and the STM32U5 a Cortex M33 Ultra-low-power.

I looked at the IT8951 firmware, and you need to make some updates on your project to make it works.

On the STM32F4 they use the SPI4 (IT8951.h file) which is not available on the STM32U5, I suggest you to use the SPI1 instead more accessible on the STM32U5 discovery kit.
You need to update your IT8951.c file according to the modification :
- SPI1 -> RCC_APB2
- MOSI -> PE15
- MISO -> PE14
- SCK -> PE13
- CS-> PE12
For HRDY and RST you can that any pin that you want, just make sure they match your description on your IT8951.c (InterfaceInit() function) and IT8951.h files. I suggest you to use the pins near on your board to the SPI1 (PA8, PC1).

In attached the schematic for the STM32U5 discovery kit (B-U585I-IOT02A).

Best Regards,

A.MVE

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Aime · ‎2022-06-22