7 seg display w/I2C Backpack, 1 working, 2 others identical

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SequencesShortened
 
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Joined: Thu Jan 16, 2014 5:14 pm

7 seg display w/I2C Backpack, 1 working, 2 others identical

Post by SequencesShortened »

Hi,

I have 3 x 0.56" 4-Digit 7-Segment Display w/I2C Backpack. Prototyping with a Raspberry Pi exactly as per the tutorial at

http://learn.adafruit.com/matrix-7-segm ... i/overview

My first assembly worked absolutely fine, so I moved on to assemble and test the second module. (nb. I am only running one module at a time, I will be setting up an independent power source before running them together on different addresses) The module is identified on address 0x70 exactly as expected using

Code: Select all

sudo i2cdetect -y 1
All good so far. But then running the ex_7segment_clock.py example, there is nothing displayed on digits 1,2, colon, 3 - only something random appearing on digit 4 - and flashing at 1Hz as the colon is supposed to do! I double and tripple checked my soldering and wiring and found no reason for concern, and swapped back to the working first module and all is still well.

So I assembled the 3rd module, and it has exactly the same problem as the second!

I wrote a test script to write 0xFFFF to all buffers as follows:

Code: Select all

#!/usr/bin/python
from Adafruit_7Segment import LEDBackpack
led = LEDBackpack()
led.clear()
for row in range(0,7):
  led.setBufferRow(row,0xFFFF)
With the working module, the display is fully ON exactly as expected

Image

But the 2 non-working modules (one green, one yellow) show an identical display - just the colon, plus the segments as shown below illuminated in digit 4:

Image

Image

Given that both "non-working" modules have exactly the same behaviour I'm holding out that it's something that may be known about - thanks for any help or insight anybody may be able to provide!

Cheers

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adafruit_support_mike
 
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Joined: Thu Feb 11, 2010 2:51 pm

Re: 7 seg display w/I2C Backpack, 1 working, 2 others identi

Post by adafruit_support_mike »

Check the positions of the decimal points. It looks like the two non-working ones are upside down, but the images above are a bit too small for me to be sure.

SequencesShortened
 
Posts: 2
Joined: Thu Jan 16, 2014 5:14 pm

Re: 7 seg display w/I2C Backpack, 1 working, 2 others identi

Post by SequencesShortened »

:oops:

Thanks Mike! Time to dig out my de-soldering pump!

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