Using a modified version of the HAGL graphics library and HAGL Pico mipi driver we can attach 3 or more displays to an RP2040.
If you cannot compile yourself build directory contains a recent firmware.
Credit for this mostly belongs to Mika Tuupola who is the original author of all the graphics libraries and example code. My contribution merely consists of modifying the libraries to support multiple displays.
Below instructions assume you do not have Raspberry Pi Pico SDK installed yet.
$ git clone --recursive https://github.com/raspberrypi/pico-sdk.git
$ git clone --recursive https://github.com/james-bryant/pico_effects
$ cd pico_effects/build
$ cmake ..
$ make -j8
If the SDK is already installed you can pass the installation path manually.
$ git clone --recursive https://github.com/james-bryant/pico_effects
$ cd pico_effects/build
$ cmake .. -DPICO_SDK_PATH=../pico-sdk
$ make -j8
You can then "flash" the firmware by putting the Pico into BOOTSEL mode and copying the uf2 file to the automatically mounted volume.
$ cp firmware.uf2 /run/media/<username>/RPI-RP2/
If you are using macOS the command would be the following.
$ cp firmware.uf2 /Volumes/RPI-RP2
Alternatively you can use picotool to flash the firmware.
$ picotool load firmware.uf2 -f
The hardware used in this example is a Raspberry Pi Pico board and the three display modules.
The modules I used can be found here: https://www.aliexpress.us/item/2251832728153401.html Similar display modules should work as long as you adjust the config parameters accordingly.
The following tables has the wiring. All three displays share a SPI port, so the SDA, SCL, and DC pins connect to all three displays.
| Pico Pin | GPIO | display1 Pin | display2 pin | display3 pin |
|---|---|---|---|---|
| 18 | VCC | VCC | VCC | |
| 36 | GND | GND | GND | |
| 15 | 11 | SDA | SDA | SDA |
| 14 | 10 | SCL | SCL | SCL |
| 11 | 8 | DC | DC | DC |
| 12 | 9 | CS | ||
| 16 | 12 | RST | ||
| 7 | 5 | CS | ||
| 6 | 4 | RST | ||
| 5 | 3 | CS | ||
| 4 | 2 | RST |
This project was merely a proof of concept for other projects I'm working on. I do not plan to develop this example project any further short of any bug fixes.
MIT No Attribution (MIT-0). Please see LICENSE for more information.