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New version of the 128x32 (STEMMA) display remains off after
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New version of the 128x32 (STEMMA) display remains off after

by goyankees on Thu Oct 14, 2021 6:16 am

New version of the 128x32 (STEMMA) display remains off after power cycle.

I have two generations of the 128x32 OLED display. My PCB is based on a standalone ATMega328P which I'm programming through an Arduino Uno (as ISP). When I cycle power to my PCB (or the UNO for that matter) the old one (#931) comes back up normally as expected. The new one (#4440), though, remains blank after a power cycle.
If I re-upload the code to the ATMega328P it then works normally again.

The code calls <Adafruit_SSD1306.h> and as I said is working normally on both screens except for the power cycle scenario.

For the new displays is there an extra line of code that needs to be in there to bring it back up after turning it off/on?

Thanks.

goyankees
 
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Re: New version of the 128x32 (STEMMA) display remains off a

by mikeysklar on Fri Oct 15, 2021 7:10 pm

How long of a delay do you have in the code during initialization before communicating with the display? That is the most common reason we see displays not come up.

from the troubleshooting area of our guide:

The OLED driver circuit needs a small amount of time to be ready after initial power. If your code tries to write to the display too soon, it may not be ready. It will work on reset since that typically does not cycle power. If you are having this issue, try adding a small amount of delay before trying to write to the OLED.
In Arduino, use delay() to add a few milliseconds before calling oled.begin(). Adjust the amount of delay as needed to see how little you can get away with for your specific setup.

mikeysklar
 
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Re: New version of the 128x32 (STEMMA) display remains off a

by goyankees on Mon Oct 18, 2021 9:25 am

thanks, that did the trick.

goyankees
 
Posts: 3
Joined: Wed Jan 23, 2019 4:21 pm

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