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Quad Alphanumeric Display, SKU-1912, No I2C device.
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Quad Alphanumeric Display, SKU-1912, No I2C device.

by antoniob on Wed Dec 18, 2019 7:30 am

I have gone through two displays, two M0 Express Feathers and still no luck in getting either Quad Alphanumeric display to function...
Using CircuitPython to test, I continuously get the following error;

Code: Select all | TOGGLE FULL SIZE
Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.
main.py output:
Traceback (most recent call last):
  File "main.py", line 23, in <module>
  File "adafruit_ht16k33/ht16k33.py", line 52, in __init__
  File "adafruit_bus_device/i2c_device.py", line 78, in __init__
  File "adafruit_bus_device/i2c_device.py", line 76, in __init__
ValueError: No I2C device at address: 70


Wiring and code examples taken from the following pages;

https://learn.adafruit.com/micropython- ... cuitpython
https://learn.adafruit.com/adafruit-led ... phanumeric

CircuitPython version: Adafruit CircuitPython 4.1.0 on 2019-08-02; Adafruit Feather M0 Express with samd21g18

All libraries are the latest available. Using Mu 1.0.2 to test and connect.

The backpack connections to the feather have been checked for continuity and signals; wired as shown in the example.
LED backpack connected as such;

M0 USB --> VCC
M0 3v3 --> V12c
M0 GND --> GND
M0 SCL -->SCL
M0 SDA --> SDA

Alpha LED partnumber: A1906129, purchase with with SLU-1912 backpack.

The CircuitPython test code is

Code: Select all | TOGGLE FULL SIZE
# Basic example of setting digits on a LED segment display.
# This example and library is meant to work with Adafruit CircuitPython API.
# Author: Tony DiCola
# License: Public Domain

import time
import board
import busio as io
# Import the HT16K33 LED segment module.
import adafruit_ht16k33.segments

# Create the I2C interface.
i2c = io.I2C(board.SCL, board.SDA)

# Create the LED segment class.
# Or this creates a 14 segment alphanumeric 4 character display:
display = adafruit_ht16k33.segments.Seg14x4(i2c)

# Clear the display.
display.fill(0)
display.show()

display[0] = 'C'
display[1] = 'I'
display[2] = 'P'
display[3] = 'Y'
display.show()

time.sleep(2)

display.print('CPY!')
display.show()

Am I missing something???

antoniob
 
Posts: 23
Joined: Tue Jul 09, 2013 2:47 am

Re: Quad Alphanumeric Display, SKU-1912, No I2C device.

by antoniob on Wed Dec 18, 2019 8:58 pm

SOLUTION Found...

The wiring notes indicate...

Wiring!
Nex up, let's wire it up to an Arduino. We'll be using an Arduino.
Connect CLK to the I2C clock - on Arduino UNO thats Analog #5, on the Leonardo it's Digital #3, on the Mega it's digital #21
Connect DAT to the I2C data - on Arduino UNO thats Analog #4, on the Leonardo it's Digital #2, on the Mega it's digital #20
Connect GND to common ground
Connect VCC+ to power - 5V is best but 3V will work if that's all you've got (it will be dimmer)
Connect Vi2c to your microcontroller's logic level (3-5V) - If you're using an Arduino, this is almost certainly 5V. If its a 3V Arduino such as a Due, connect it to 3V
Both Vi2c and Vcc MUST be connected to 3 to 5VDC! Vcc is for the LED driver power, Vi2c is what sets the logic level for communication to the chip.


I connected VCC to USB power (5V on the M0 Express board) and Vi2c to 3v3 from the M0 Express... Nope, not gonna work.
Connecting both to VCC and Vi2c to 3v3 from the M0 Express was successful.
The display now works.

antoniob
 
Posts: 23
Joined: Tue Jul 09, 2013 2:47 am

Please be positive and constructive with your questions and comments.