GC9A01 display issue on Raspberry Pi 3 - no text is displayed

[mytja]

Hello,
So, I bought one of GC9A01 chip based SPI displays off AliExpress (not a link to AliExpress), and I started testing it. I use CircuitPython with latest adafruit-blinka installed on my Raspberry Pi 3B.
So, I installed all necessary libraries:

• CircuitPython GC9A01
• Blinka DisplayIO

I'm using following code:

import time
import board
import math
import busio
import terminalio
import displayio
from adafruit_display_text import label
import gc9a01

# Release any resources currently in use for the displays
displayio.release_displays()

spi = board.SPI()

# Make the displayio SPI bus and the GC9A01 display
display_bus = displayio.FourWire(spi, command=board.D25, chip_select=board.D18, reset=board.D27)
display = gc9a01.GC9A01(display_bus, width=240, height=240)

# Make the main display context
main = displayio.Group()
display.show(main)

# Draw a text label
text = "Hello\nWorld!"
text_area = label.Label(terminalio.FONT, text=text, color=0xFFFF00,
                        anchor_point=(0.5,0.5), anchored_position=(0,0))
text_group = displayio.Group(scale=2)
text_group.append(text_area) 
main.append(text_group)

# Animate the text 
theta = math.pi
r = 75
while True:
    print(time.monotonic(),"hello")
    text_group.x = 120 + int(r * math.sin(theta))
    text_group.y = 120 + int(r * math.cos(theta))
    theta -= 0.05
    time.sleep(0.01)

The problem is, that this code gives me following output (sorry my hands are shaking):

20220320_150302.mp4

So, I decided to use Pi Pico to test if display is faulty. So I flashed it with latest CircuitPython firmware, installed everything, modified my code to Pico's pins, and here is the result:

20220320_183037.mp4

I really don't think it's the CircuitPython GC9A01's fault. I also checked wiring on my Raspberry Pi 3 like a million times. So, my guess is that it's blinka-displayio's fault, as Pico uses CircuitPython's displayio, meanwhile Pi 3 uses blinka-displayio, which is a port to Unix & Unix-like operating systems.

I'm also not using integrated (hardware) Chip-Select pin, as it's not recommended.

Let me know what you think is the issue.
Awaiting your response and thank you for everything upfront 🙏

---

Code source

[makermelissa]

Currently the Blinka Displayio implementation is not complete and is only a subset of CircuitPython's Displayio. It has not been tested with this display. It's likely using part of the codebase that is missing.

[makermelissa]

#114 should get it working if you still have the display and are interested. Otherwise, I will likely just close this issue after it's merged.

[makermelissa]

Closing as this should be fixed.