Minor changes to the ST7789 1.47 Example that were required to work with raspberry pi pico w

[markmcgookin]

Small changes to work with Circuit Python 8 Beta 4 on Raspberry Pi Pico. board.SPI didn't exist and needed to be changed to busio.SPI.

The Dx reference for pins doesn't work and needs updated to be GPx (for the raspberry pi pico at least)

I am unaware if this is across the board, or just for the pico w or just CP8. But I thought I would share as it's taken me quite a while to figure this out.

Also... again this might be an eccentricity of the waveshare 1.47 board, but I had to power it from external 3v3 BEFORE booting my board for this code to work. When trying to drive it from any of the Picos outputs, the screen was either incredibly dim or simply didn't work, it would be great to mention that in documentation on the site somewhere if that's common.

[markmcgookin]

Not sure if I've broken something with the code change or the CI tests are on the fritz... looks like someone was working on them recently. If it's something up with the code please let me know.

[tekktrik]

You can merge main into your code to grab any new CI changes, but the specific issue the CI has is that it wants to reformat the files. You can make the changes it wants to make by running pre-commit locally and then pushing those changes.

[markmcgookin]

I only just formed main so that must be it. I’ll have a look thanks Sent from my iPhoneOn 13 Nov 2022, at 03:18, Alec Delaney ***@***.***> wrote: You can merge main into your code to grab any new CI changes, but the specific issue the CI has is that it wants to reformat the files. You can make the changes it wants to make by running pre-commit locally and then pushing those changes. —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you authored the thread.Message ID: ***@***.***>

[FoamyGuy]

I can try to merge this and resolve CI issues.

I think we will not want to change the example to use only the pico-w pins though. Including them is fine, but we should keep the originals, as they are used by guides and other resources on other devices. In cases like this where there are alternatives it's typical to include a commented out section with the alternative pins or configuration details. I think we'd want something like that here.

[FoamyGuy]

This is passing the CI checks now, it did need just some minor code formatting changes.

I think we will want to keep the existing pins and SPI setup as an option for anyone using non-pico microcontrollers.

I would recomend adding the new option like this so that people can uncomment the one they need easily:

# built-in, silkscreen labelled SPI bus  
spi = board.SPI()
tft_cs = board.D5
tft_dc = board.D6
tft_rst = board.D9

# pico and pico-w pins for SPI bus
# spi = busio.SPI(board.GP2, board.GP3, board.GP4)
# tft_cs = board.GP5
# tft_dc = board.GP6
# tft_rst = board.GP7

[markmcgookin]

Just making this change now. Would we not still need to update the board.SPI() call to buisio.SPI(board.D2, board.D3, board.D4) though.

Looking here it seems that busyio is now a requirement for I2C or SPI.

Board does have values for MISO, MOSI and SCK which could be used, but that might not work for the pico as it has multiple pins that can be used for them... how about if I change it to this:

# built-in, silkscreen labelled SPI bus  
spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
tft_cs = board.D5
tft_dc = board.D6
tft_rst = board.D9

# If using a Raspberry Pi Pico or Pico-w 
# Uncomment the below code to use GP (General Purpose) pins 
# instead of D (Digital)

# spi = busio.SPI(board.GP2, board.GP3, board.GP4)
# tft_cs = board.GP5
# tft_dc = board.GP6
# tft_rst = board.GP7

[markmcgookin]

ah sorry man, I've broken the CI again... not sure what I am doing wrong, just using VSCode for these changes.

Error: black....................................................................Failed
- hook id: black
- files were modified by this hook

Error: reformatted examples/st7789_172x320_1.47_simpletest.py

[makermelissa]

ah sorry man, I've broken the CI again... not sure what I am doing wrong, just using VSCode for these changes.

You should just be able to run pre-commit and then push any changes. See https://learn.adafruit.com/creating-and-sharing-a-circuitpython-library/check-your-code

[FoamyGuy]

I reverted the change so we use board.SPI instead of busio in that case. Pylint needed a little help after that due to unused import so I moved it down to the commented section.

This looks good to me now.

Thanks for updating the example to make it easier for folks with Pico devices @markmcgookin!