Make a screen work without using get_device() from demo_opts

[raf59]

I use a st7735 device on a RPI3b. It's working if I use the get_device() function from demo_opts.py as in luma.examples. I use the following command :

python3 tst_luma.py --display st7735 --interface=spi --spi-bus-speed=16000000 --gpio-reset=24 --gpio-data-command=23 --gpio-backlight=18 --width=160 --height=128 --backlight-active=high --rotate=3

I'd like to define the rotation of the screen in my program. I tried these following lines instead of get_device() but it doesn't work. Nothing is happening.

from luma.core.interface.serial import spi
from luma.lcd.device import st7735
serial = spi(port=0, device=0, gpio_DC=23, gpio_RST=24, cs_high=True, bus_speed_hz=16000000)
device = st7735(serial_interface=serial, width=160, height=128, rotate=3)

What am I doing wrong?

Thanks in advance

[thijstriemstra]

@raf59 you probably need to specify amount of degrees rotation instead.

[raf59]

Thanks for your answer @thijstriemstra ! I'm not sure to understand. According to the doc, "rotate" option can accept only 0, 1, 2 or 3. How would you specify the amount of degrees rotation ? For the moment, even without defining a rotation, the screen doesn't turn on if I don't get the "device" object using get_device().

[rm-hull]

Try removing cs_high=True, when initializing SPI

[raf59]

Oh thank you very much @rm-hull . I don't know why I added this option. Probably a bad copy-paste. Now the screen is working but the backlight keeps off. I think it's due to the backlight-active option. I don't know how to pass this option to the device when initializing it. The only way I found to turn the backlight on is to manually set the GPIO 18 high.

import RPi.GPIO as GPIO
GPIO.setup(18, GPIO.OUT)
GPIO.output(18, 1)

Is there a cleaner way to do it ?

[rm-hull]

https://luma-lcd.readthedocs.io/en/latest/python-usage.html#backlight-control

[rm-hull]

oh, you can pass active_low=True|False when initializing the device to indicate whether the backlight is active low or high

[raf59]

Perfect !!! Now, everything is working fine ! Thank you for your answer and also for this awesome library. Good job!