Fix M5Stack CoreS3 boot crash

[CDarius]

This PR fixes the issue #11009
The problem was the SPI bus definition. The GPIO35 is either the MISO pin on the M5Bus but also the display DC signal.
I have changed the SPI definition removing the MISO pin.
I made the same change also for the CoreS3 SE

[dhalbert]

Thanks for fixing this.

Are the SPI pins available externally, or are they just used for SD and the display D/C? A board.SPI() that doesn't have a MOSI is not very useful. I wonder if we should just remove board.SPI() entirely if it can't be used as a regular SPI.

[CDarius]

On the CoreS3 the SPI use the following gpios:

• SCK -> GPIO36
• MOSI -> GPIO37
• MISO -> GPIO35

This SPI bus is used for the display, the SD card and exposed on the M5Bus (on the back)
Unfortunately the GPIO35 is also the DC signal for the display.

I can remove the SPI definition from mpconfigboard.h (and pins.c) but then I should probably create the display SPI bus in board.c. Do you prefer to go in this direction?

[dhalbert]

I can remove the SPI definition from mpconfigboard.h (and pins.c) but then I should probably create the display SPI bus in board.c. Do you prefer to go in this direction?

I guess this is the best way. Maybe also rename the pins to TFT_SCK, TFT_MOSI, TFT_DC.

Most people trying to do regular SPI on the supposed "SPI" pins are going to be disappointed. I looked at the Arduino pin defs for the board and they also say MISO for pin 35. If someone wants SPI they should use other pins.

[dhalbert]

Thanks - now we can remove the DEfAULT_SPI_* definitions too, since there is no board.SPI().

[dhalbert]

Great - thanks for fixing this!