Pixel artifacts on ST7735

[sgjava]

I'm using this https://www.amazon.com/gp/product/B01J76ZGMY ST7735 on my ODROID C1+ which I have SSD1306 and SSD1331 working fine. When I use the examples or a sample program I wrote it leaves pixel artifacts on the bottom and right side of the display. See attached image:

Also the back light only works on "high" using the examples. "low" displays a black screen.

[thijstriemstra]

Can you show us the example code to doublecheck for errors?

[sgjava]

Sure for the clock.py I used:

sudo python clock.py -d st7735 -i spi --spi-port 0 --spi-device 0 --gpio-data-command 24 --gpio-reset 25 --gpio-backlight 13 --width 160 --height 128 --backlight-active high

My little sample:

import time
from RPi import GPIO
from luma.core.interface.serial import spi
from luma.core.render import canvas
from luma.lcd.device import st7735

GPIO.setmode(GPIO.BOARD)
GPIO.setwarnings(False)
serial = spi(port=0, device=0, gpio=GPIO, gpio_DC=18, gpio_RST=22)
device = st7735(serial)

with canvas(device) as draw:
    draw.rectangle(device.bounding_box, outline="white")
    draw.text((3, 3), "Hello", fill="white")

time.sleep(10)

Both result in the exact same artifacts.

[thijstriemstra]

what if you use 161x31 or 159 x 29? just a thought

[sgjava]

Anything except 160x128 results in Unsupported display mode: 159 x 127

[sgjava]

OK, I tried another little sample piece of code and it looks like the canvas is shifted as the following displays a bounding box (with 2 rows of pixel clutter at the bottom):

with canvas(device) as draw:
    draw.line((0, 2, 159, 2), fill="white")
    draw.line((1, 0, 1, 127), fill="white")
    draw.line((0, 127, 159, 127), fill="white")
    draw.line((159, 0, 159, 127), fill="white")
time.sleep(5)

[rm-hull]

So the different manufacturers map the screen to different memory offsets. I had to add h-offset and v-offset for the ST7735 ...

See https://github.com/rm-hull/luma.core/blob/master/luma/core/cmdline.py#L238 and https://github.com/rm-hull/luma.lcd/blob/master/luma/lcd/device.py#L146

[rm-hull]

Sorry not paying attention properly, thought this was about ssd1351... Try fiddling with the --h-offset and --v-offset params either +/-1 or 2 until it displays properly

[rm-hull]

The size should be 160x128. Use the examples demo.py script as a reference to get the offsets correct

[sgjava]

I'll try that tomorrow and check back with the results.

[thijstriemstra]

ah yeah... you can force it by removing this check though: https://github.com/rm-hull/luma.lcd/blob/master/luma/lcd/device.py#L154

But it's just a wild guess, I don't expect it to improve.

[sgjava]

--h-offset 1 --v-offset 2 worked perfect!

sudo python clock.py -d st7735 -ipi --spi-port 0 --spi-device 0 --gpio-data-command 24 --gpio-reset 25 --gpio-backlight 13 --width 160 --height 128 --backlight-active high --h-offset 1 --v-offset 2