ReadID from ST7789V fails on NUCLEO-H745-ZIQ with X-NUCLEO-GFX02Z1$AZ2

[AndreasKurz]

Hello 🙂

I'm trying to get the mentioned display expansion board working with my NULCEO board. I already downloaded the X-DISPLAY examples and found a configured ioc file for an H723 so I replicated all the settings to match my H745 one.

Unfortunately the software fails already with a call to BSP_LCD_Init() -> LCD_Probe() which then tries to read the ID from the st7789v which returns something else than expected and then goes into the error handler. Also there's no datasheet for the display I don't know if the ID I'm getting is something else valid or just garbage.

I've CubeMX version 6.12 but the X-DISPLAY software packs highlights it's only compatible with version 6.7 to 6.8. So maybe that's also an issue?

At the moment I've absolutely no idea how to investigate this issue further. My expectations were that it's easier to setup ST hardware when they're listed as compatible.

Thanks for your help in advance.

[EmbDev]

What is the ID that gets returned by the display?

[AndreasKurz]

The "st7789v_recv_data" call reads 0x242424 which is compared to the expected ID of "0x858552" then bit-manipulated to 0x484848.

0x484848 is then compared in LCD_Probe with the expected ID noted above – which doesn't match – and then returns "BSP_ERROR_UNKNOWN_COMPONENT"

Does that help? If you need more information or the respective snippets from the generated Code then just let me know 🙂

[EmbDev]

Seems like the data is just one bit-shift away from the expected data.
Assuming you are using SPI as an interface, could you check the SPI phase and polarity settings?

[AndreasKurz]

I'm using the FMC to access the display.

Maybe my description was a bit off. The read ID of 0x242424 is manipulated to 0x484848.
The expected value for the read ID would be 0x858552. The expected ID is never manipulated.

I really can't find anything how to setup this besides copying settings from the H723 example.