STM32F401 Blackpill with ILI9341 TFT

[djcleckie]

I can't get a F401 Blackpill to work - I just get a Grey Screen yet it works with a F103 Bluepill.

I have a test jig with a 40 pin ZIF socket so I can swap between a STM32F103 Blue Pill and a STMF401 BlackPill.

I am testing with TFT_Print_Test

I am using Setup32_ILI9341_STM32F103.h

Pin wiring to the default for above.

It works fine with a BluePill when I select a F103 board.
All I do is change the Board in the Arduino IDE from an F103 to a F401 and re-compile and upload.

No display on the ILI9341 TFT but I also have blink running and its fine.

As far as I can see the F103 and the F401 have the same SPI pins.

Its got me puzzled.

I also have the same TFT working fine with an ESP32

I also have a Nucleo64 STM32F401 board and it behaves exactly the same.

Issue seems to be relate to the F401 as the F103 is fine.

Anybody got any ideas?
I plan to put an oscilloscope onto the SPI pins and see if there is a difference.
Could the F401 be using a different SPI mode to the F103?

Dave