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ST7735S Library for Teal Tab screen on Pico

Libraries
#1

I’ve added the library and dependencies for the forked library which should support my teal tab LED screen.

If I understand correctly, I should be using the initS() method for initialisation, but this method does not seem to be available in code completion and won’t compile.

When I install the library, it automatically installs this:

Which I assume it extends. Perhaps there is a conflict as the header + cpp files have the same name? How should I resolve this?

Thanks!

#2

You’re saying when you put lib_deps = mbed-cognoscan/Adafruit_ST7735 in the platformio.ini it installs adafruit/Adafruit ST7735 and ST7789 Library?

Is your project using Arduino or mbed as its framework?

#3

I had installed adafruit/Adafruit ST7735 and ST7789 previously but realised it didn’t support the S series so I manually deleted it because it would uninstall via the UI. Made sure there was no reference in the platformio.ini and it was gone from the installed libraries tab. Reappears if I add / compile with the ST7735S lib.

I’m using arduino for framework.

#4

But the mbed-cognoscan/Adafruit_ST7735 library only supports mbed-os (https://registry.platformio.org/libraries/mbed-cognoscan/Adafruit_ST7735/compatibility). The Pico might be an extremely special case here because its default Arduino core is built on the basis of mbed-os, but given that the beforementioned library was released 6 years ago, it must have been written against an ancient mbed-os version.

In any case, if you attempt to install mbed-cognoscan/Adafruit_ST7735 PlatformIO should by default refuse to install that because of the compatibility check with mbedos (unless lib_compat_mode was changed).

Could you share the complete platformio.ini?

#5

It also might be better if you use the latest (real) Adafruit ST7735 library and backported the needed changes (Adafruit_ST7735 - Clone of the Adafruit ST7735 library, updated for… | Mbed) to that. Seems like just a new init command list and an inversion of CS to me, nothing fancy.

#6 
; PlatformIO Project Configuration File
;
;   Build options: build flags, source filter
;   Upload options: custom upload port, speed and extra flags
;   Library options: dependencies, extra library storages
;   Advanced options: extra scripting
;
; Please visit documentation for the other options and examples
; https://docs.platformio.org/page/projectconf.html

[env:pico]
platform = raspberrypi
board = pico
framework = arduino
lib_deps = 
	adafruit/Adafruit NeoPixel @ ^1.10.5
	khoih-prog/RP2040_PWM @ ^1.3.0
	adafruit/Adafruit BusIO @ ^1.11.6
	adafruit/Adafruit GFX Library @ ^1.11.1
	adafruit/Adafruit seesaw Library @ ^1.6.2
	mbed-cognoscan/Adafruit_ST7735@0.0.0+sha.20134e1718b2
#7

Thanks, that might be my best option. Although I’m new to C++ it’ll definitely be an experience!

#8

Just for fun, with a few compile fixes one can indeed get the 6 year old library to compile, can you check out GitHub - maxgerhardt/pico-st7735s-test?

#9

Thanks for taking the time to have a look.

I checked it out and was able to compile successfully. I had to change the following lines to set the MISO to Not Connected to get it to work.

    tftSPI = new mbed::SPI(TFT_MOSI, NC, TFT_SCLK);
    tft.SetSPI(tftSPI);
    tft.initS(); // initialize ST7735S chip

I’ve now got some stuff on the screen but the colour is wrong and there’s some garbled pixels. Will investigate further…

#10

If you want to check out of a different path, there were 2 pull requests at the Adafruit library page for ST7735S support, in particular https://github.com/adafruit/Adafruit-ST7735-Library/pull/126 seems to be the newest.

Could you test out the alternative GitHub - maxgerhardt/pico-st7735s-test2 if you have time?

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#11

Excellent stuff. I had to uncomment this line:

Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_MOSI, TFT_SCLK, TFT_RST);

Now everything works as expected. Many thanks!

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