Sh1106 SPI in Breakout Garden - can't get it working

Support
1

I’ve installed the software as described:

sudo pip install git+git://github.com/rm-hull/luma.oled.git#egg=luma.oled

but can’t get the bounce demo to work - I’ve tried the sh1106 in both SPI slots with the same result (–spi-device = 0 and 1)

pi@raspberrypi2:~/luma.examples/examples $ python bounce.py --display sh1106 --height 128 --rotate 2 --interface spi --gpio-data-command 9 --spi-device 0
Version: luma.oled 3.6.0 (luma.core 1.17.1)
Display: sh1106
Interface: spi
Dimensions: 128 x 128

/usr/local/lib/python3.7/dist-packages/luma/core/interface/serial.py:198: RuntimeWarning: This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable warnings.
self._gpio.setup(pin, self._gpio.OUT)
Traceback (most recent call last):
File “bounce.py”, line 80, in
device = get_device()
File “/home/pi/luma.examples/examples/demo_opts.py”, line 63, in get_device
device = cmdline.create_device(args)
File “/usr/local/lib/python3.7/dist-packages/luma/core/cmdline.py”, line 218, in create_device
device = Device(serial_interface=interface(), **vars(args))
File “/usr/local/lib/python3.7/dist-packages/luma/core/cmdline.py”, line 157, in spi
gpio=self.gpio or GPIO)
File “/usr/local/lib/python3.7/dist-packages/luma/core/interface/serial.py”, line 306, in init
self._spi.cshigh = cs_high
SystemError: error return without exception set

The breakout garden seems fine as I have a bme680 plugged in which is working OK. Allthough this doesn’t prove SPI bus is ok.

Also checked that spi is not commented out in /boot/config.txt

Any suggestions are much appreciated

Pete

2

Got it working, but I don’t understand why!

I had to add the argument --spi-cd-high False

I will try the rest of the examples to confirm that the others are working

3

All the examples that I have tried worked ok with --spi-cd-high False

4

Just some FYI stuff on the Breakout Garden
The Back SPI slot is cs=0 and the Front is cs=1
And you can just use cs=1, instead of all that BG_SPI_CS_FRONT stuff.
Also the Back SPI slot uses GPIO 18 for backlight and the Front uses GPIO 19 for Backlight. I have the Mini SPI i2c, it uses the Front values.

Is CD the DC pin?

5

I don’t know, the error message mentioned cd-high so I tried playing with the true/false settings. So it worked but I don’t know why. Hope someone else can tell me. Also if this is needed by everyone then the instructions need updating.

6

Just realised that spell check has changed cs to cd in my replies. So I needed --spi-cs-high False, I’m guessing cs is chip select.

7

Yes cs is chip select. Use the wrong one and the display won’t do anything.