Display-o-tron and Rpi3 not working together

Support
1

Hi,
Bought the DOT HAT ( https://shop.pimoroni.com/products/display-o-tron-hat ) and installed everything nicely. When running the demo files it gives:

pi@raspberrypi:~/Pimoroni/displayotron/dothat/basic $ sudo python backlight.py

This example shows you a feature of the Dot HAT backlight.
You should see a rainbow sweep across the whole display!

Press CTRL+C to exit.

Traceback (most recent call last):
File “backlight.py”, line 9, in
import dothat.backlight as backlight
File “/usr/local/lib/python2.7/dist-packages/dothat/backlight.py”, line 1, in
import sn3218, colorsys, math
File “/usr/local/lib/python2.7/dist-packages/sn3218.py”, line 112, in
enable_leds(0b111111111111111111)
File “/usr/local/lib/python2.7/dist-packages/sn3218.py”, line 60, in enable_leds
[enable_mask & 0x3F, (enable_mask >> 6) & 0x3F, (enable_mask >> 12) & 0X3F])
IOError: [Errno 5] Input/output error

pi@raspberrypi:~/Pimoroni/displayotron/dothat/basic $ python backlight.py

This example shows you a feature of the Dot HAT backlight.
You should see a rainbow sweep across the whole display!

Press CTRL+C to exit.

Traceback (most recent call last):
File “backlight.py”, line 9, in
import dothat.backlight as backlight
File “/usr/local/lib/python2.7/dist-packages/dothat/backlight.py”, line 1, in
import sn3218, colorsys, math
File “/usr/local/lib/python2.7/dist-packages/sn3218.py”, line 112, in
enable_leds(0b111111111111111111)
File “/usr/local/lib/python2.7/dist-packages/sn3218.py”, line 60, in enable_leds
[enable_mask & 0x3F, (enable_mask >> 6) & 0x3F, (enable_mask >> 12) & 0X3F])
IOError: [Errno 5] Input/output error
pi@raspberrypi:~/Pimoroni/displayotron/dothat/basic $

And:

pi@raspberrypi:~/Pimoroni/displayotron/dothat/basic $ i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: – -- – -- – -- – -- – -- – -- –
10: – -- – -- – -- – -- – -- – -- – -- – --
20: – -- – -- – -- – -- – -- – -- – -- – --
30: – -- – -- – -- – -- – -- – -- – -- – --
40: – -- – -- – -- – -- – -- – -- – -- – --
50: – -- – -- – -- – -- – -- – -- – -- – --
60: – -- – -- – -- – -- – -- – -- – -- – --
70: – -- – -- – -- – --

I’m no expert but neither a true noob. Where do I went wrong here ?

2

The backlight is run over SPI, though you should still see something using i2cdetect.

So my question would be 2 fold:

  • are you attaching the HAT directly to the Pi, or via other means?
  • did you run the one-line installer to get this far?

… I suspect the answer is yes in both cases but I just want to be sure you got SPI communication enabled and proper powering of the board.

Edit: actually the backlight is driven by the SN3218, so that’s over i2c. Either way both interfaces are required.

3

HAT is attached directly
yes I did run the one-line installer.

After a LOT of Google it now says this:

pi@raspberrypi:~/Pimoroni/displayotron/dothat/basic $ ./backlight.py

This example shows you a feature of the Dot HAT backlight.
You should see a rainbow sweep across the whole display!

Press CTRL+C to exit.

Traceback (most recent call last):
File “./backlight.py”, line 9, in
import dothat.backlight as backlight
File “/usr/local/lib/python2.7/dist-packages/dothat/backlight.py”, line 1, in
import sn3218, colorsys, math
File “/usr/local/lib/python2.7/dist-packages/sn3218.py”, line 112, in
enable_leds(0b111111111111111111)
File “/usr/local/lib/python2.7/dist-packages/sn3218.py”, line 60, in enable_leds
[enable_mask & 0x3F, (enable_mask >> 6) & 0x3F, (enable_mask >> 12) & 0X3F])
IOError: [Errno 5] Input/output error

4

you could try some of the other examples, such as touch.py, but by the looks of it your unit seems DOA.

5

I did and:

Nooooooooo!! I waited for days to arrive and now it’s DOA ?!

Ok, what’s next ?

6

email support@pimoroni.com and they’ll take it from there.