Which GPIO Pins on PiTFT2.2?


#1

I’ve got the following display ( https://shop.pimoroni.com/collections/electronics/products/adafruit-pitft-2-2-hat-mini-kit-320x240-2-2-tft-no-touch ). It says on the page it uses the SPI pins and lists 4 names and GPIO#25.
If you look at https://pinout.xyz/pinout/spi# there appear to be two lots of SPI pins. Does anyone know which ones the board uses?

It’s also confusing because the buttons underneath the display are labelled 17, 22, 23, and 27. However, 23 is one of the SPI pins. Also, GPIO#25 is a ground pin so it seems odd to say that the board uses it when it’s not really a GPIO pin, or have I misunderstood something?

Thanks


#2

you are confusing physical and bcm notation… the front page at pinout.xyz explains the difference.

… very few (sensible) litterature will ever use physical notation, though if they don’t specifically use something like ‘bcm23’ rather than ‘pin 23’ then they are asking for trouble. That said, as you noted, GPIO #23 would always imply this is not a physical notation, GPIO being short for General Purpose Input/Output.

Anyway, all that to say that, armed with the above clarification, you should be able to work out what pins this board uses. It would also use the spi0 bus, which technically makes the board compatible with older 26-pin Pis, with a bit of creativity. The second SPI bus (spi1) is seldom used in practice by board makers (IIRC a single board featured at pinout.xyz does).

I hope this helps.


#3

Thanks, I always forget about those BCM numbers (even when they stare me in the face apparently).