Waveshare Pico ResTouch LCD 2.8 SPI ST7789 display

[TimWermer]

Hello Peter,

I am trying to get the above display to work with the following code:

main_2inch8.py.txt
st7789.py.txt

I get no errors and my backlight lights up.

Can you give me a hint how to proceed?

Best regards,

Tim Wermer

[peterhinch]

It is hard for me to support hardware I don't possess, however this display should work. The Waveshare link says it comes with a MicroPython demo. Does that work?

Have you tried the procedure here? This is the best way to verify your hardware and your color_setup.py file. Also the SPI bus will appear to work even if not connected - please double check your wiring.

[TimWermer]

I am using a Pimoroni double deck for the pico. So i am pretty confident the wiring is ok.
I had a problem rshell was hanging when i was using your instructions. I found an earlier post by you with the following command that did the trick.

rshell -p /dev/ttyACM0 --buffer-size=30

The problem i am facing now is that in color_setup.py i cannot figure out why the following code breaks:

pdc = machine.Pin('Y1', machine.Pin.OUT_PP, value=0) pcs = machine.Pin('Y2', machine.Pin.OUT_PP, value=1) prst = machine.Pin('Y3', machine.Pin.OUT_PP, value=1)

Can you tell me where the attribute OUT_PP is defined?

Thanks again for your help!

[peterhinch]

The constant OUT_PP is Pyboard-specific. For other targets it should be OUT.

[TimWermer]

Ok thanks Peter!
i changed the color_setup.py into the following :

`import machine
import gc

from drivers.st7789.st7789_4bit import ST7789 as SSD

height = 320 # 2.8 inch Pico ResTouch 320240 (rowscols) display
width = 240

pdc = machine.Pin(8 , machine.Pin.OUT, value=0)
pcs = machine.Pin(9, machine.Pin.OUT, value=1)
prst = machine.Pin(15, machine.Pin.OUT, value=1)
spi = machine.SPI(1, 30_000_000, sck=machine.Pin(10), mosi=machine.Pin(11), miso=machine.Pin(12))
gc.collect() # Precaution before instantiating framebuf
ssd = SSD(spi, pcs, pdc, prst, height, width) # Create a display instance`

If i run aclock.py i get no errors but no screen what so ever.

%Run -c $EDITOR_CONTENT
Orientation: Horizontal. Reversal: False. Width: 240. Height: 320.
Start row = 0 col = 0

Do you see anything strange in the above code?

[peterhinch]

My Pico example has MISO as GPIO 8, which is the pin identified on the Pico diagram. I don't know if this matters as there is no data coming back, but it might be worth a try.

Also look at this example which is for a Waveshare display. Note that some special args were required. It's quite likely you'll need display=TDISPLAY. Unfortunately these display controller chips can be wired up in different ways: supporting the tdisplay took quite a lot of work. Going "off piste" with displays that aren't specifically tested can be challenging.

Good luck.

[peterhinch]

If you get it to run please post your setup file and I will publish it (with your attribution).

[TimWermer]

Hello Peter, i am trying to get some more info from Waveshare. They are using your code as drivers for the device. I will certainly inform you about any progress i will make!

[TimWermer]

So....remember you advised to check wiring? And i replied it is fixed on a Pimorone Pico Omnibus? Well after talking to Waveshare they asked me to click the Pico directly on the Pico ResTouch. I did so and guess what... it works.
This means that The Pico ResTouch 2.8 can be added to your compatible devices list!
Peter thank you for your patience and help.

[peterhinch]

Please could you post your setup file and I'll publish it. Thank you.

[TimWermer]

Hello Peter,

Here are the files as requested.

Thanks again for your great work!

Tim
main_2inch8.py.txt
st7789.py.txt

[peterhinch]

I hadn't spotted the changes you made to the device driver. I notice your driver initialises lut but doesn't use it. The 16-bit driver would need further adaptation to remove this if it were to be compatible with either of my GUI's. I didn't produce a 16-bit driver because of the huge buffer size. I won't publish the driver as I think the buffer is too large especially for the larger microgui codebase.

I've posted your setup adapted to use the 4-bit driver.

[TimWermer]

Using the 4-bit driver results in the attached display:

There are no errors reported.

[peterhinch]

OK, I can't see why the 4-bit driver isn't working. Given that your 16-bit version works I'm sure it can be fixed. I'll order one of these displays and (hopefully) post a solution.

[TimWermer]

Hello Peter, i can send you one if you like? More then fair for the work you do for the Community!
Just let me know. tim@wermer.org.

[peterhinch]

Thank you for the offer, Tim, but I've already ordered one. I'll post a comment once I have the 4-bit driver working.

[peterhinch]

I received a board today. This setup file enables nano-gui to run with the 4-bit driver. It can be run in landscape or portrait mode, but the SSD constructor args to achieve these modes are rather unexpected. See code comments.

[TimWermer]

Hello Peter,

That works like a charm!

For the Waveshare demo i get the following error:

AttributeError: 'ST7789' object has no attribute 'wait'

What library/repo do you use for the SD-card?

Fantastic job!

Have a good evening.

Tim

[peterhinch]

I'm glad you have it working. The file waveshare_test.py is specifically for ePaper displays and will not run on other types. I should make it produce a more friendly error message.

The file you need is the official driver sdcard.py.

I like the board except that it has no easy way to access unused GPIO pins. To run micro-gui I'll need to solder wires onto the Pico for the pushbuttons. Most users will want to connect something to the board.

[TimWermer]

I have all GPIO's available as you can see in the picture below.

I used the following product from Kiwi Electronis:

https://www.kiwi-electronics.nl/en/36-pin-stacking-header-5-pack-2875?search=pins&page=3

Maybe that helps.