SH1107

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kenidowa
 
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SH1107

Post by kenidowa »

I have been trying to use a SH1107 128x128 display. I am using CircuitPython 8.0 on a Feather RP2040 (Pico). I am using it to cycle thru three screens of information consecutively. I am using the Stemma interface over I2C to communicate with the screen and 2 other devices. The problem I am having is that it works inconsistently. By that, I mean I can run my code and it will display correctly for hours or sometime just minutes and then goes blank. No error codes or anything it just displays a black screen. I have tried changing code but it is just an unreliable display. Not sure how to proceed from here. Oh, and I have 2 of these displays and they both have the same behavior.

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mikeysklar
 
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Re: SH1107

Post by mikeysklar »

Are the displays from Adafruit? Is it this one?

https://www.adafruit.com/product/5297

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kenidowa
 
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Re: SH1107

Post by kenidowa »

That is the display I am discussing. Ordered both from Adafruit about 1-2 months ago (actually Dec. 19th). I first used "learn" and the example code to get it working. Once I got the setup working I applied it to a program to display the results of two QWIIC connected devices PCF8523 & AHT20. All on the same i2c bus.

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mikeysklar
 
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Re: SH1107

Post by mikeysklar »

When you were running the learn code with only the screen on the i2c bus were there any hangs?

Can you test your code with just the screen and then adding one additional i2c bus at a time?

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kenidowa
 
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Re: SH1107

Post by kenidowa »

Well I have run some test as you suggested. But to answer your first question, I didn't run the learn code long enough to see any blank screens and it was run with no other devices on the i2c bus.
Now, I have run a test with the just the display connected and running as close as possible
to the code that shows the blank screen (the code doesn't hang per se). It ran for about 20 hours or over 10000 cycles with no blank screen. Which is usually enough time/cycles to show the blank screen.
Then I ran a test with the display and the PCF8523 over night, it has a blank screen.
So, by itself it doesn't seem to go blank but with the PCF8523 or the PCF8523 and AHT20 I get a blank screen after several hours.
Now, I might run a test with a SSD1306 display while trying to keep the code as similar as possible.
Any other ideas would be helpful.

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mikeysklar
 
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Re: SH1107

Post by mikeysklar »

At the moment the PCF8523 sounds like the most likely culprit.

It might also be interesting to run a scenario using the SH1107 + AHT20 (removing the PCF8523).

Once you can narrow down the device that is causing the screen hang it will be easier to figure out a solution.

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kenidowa
 
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Re: SH1107

Post by kenidowa »

Well your guess is probably right. I have completed a run with the PCF8523 removed and with the AHT20 attached and operating. After about 20 hours and over 10000 cycles the screen has not failed. Whereas, it easily failed in less time and cycles in the other 2 conditions, PCF8523 only and both devices on the bus. I also ran with the SSD1306 and both devices over about the same number of cycles and time with no failures.

So it is interesting to find out what is going on.
Thanks,
Ken

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mikeysklar
 
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Re: SH1107

Post by mikeysklar »

Now that you are down to the PCF8523 being the culprit for the hang are you able to run that device alone on the i2c bus? Does it run okay with only the sample code? How long are the wire connections? Does the soldering look good?

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kenidowa
 
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Re: SH1107

Post by kenidowa »

In your replies you refer to it as a hang. So, I want to be clear the Feather Pico is running just fine, it is not hanging. The error that is occurring is on the SH1107 display. It stops displaying anything and the SH1107 screen is blank/black. The processor on the Feather is working just fine and I have print statements in the code printing to the serial port. The data coming from the one or two devices connected over the i2c bus depending on setup.
I am using the shortest wired connector sets available, I believe 50 mm. These are Adafruit wired sets.
Now, it does seem to me the PCF8523 fails most consistently, but I did have one failure with the AHT20 only connected. I did rerun that and it is at over 17000 cycles (>24 hours) with just the Feather-SH1107-AHT20 running.
The connection order for the various setups:
Feather-SH1107-PCF8523-AHT20. Feather-SH1107-PCF8523. Feather-SH1107-AHT20.
I will reexamine each board for any manufacturing issues. I have seen failures with both SH1107 displays I have.
Thanks,
Ken

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mikeysklar
 
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Re: SH1107

Post by mikeysklar »

Ken,

Thank you for clarifying between hang and the screen going blank. That is an important distinction.

Have you checked the voltage of the battery on the PCF8523?

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kenidowa
 
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Re: SH1107

Post by kenidowa »

Checked the battery, it is 3.0v.
I ran the Feather-SH1107 overnight without any other QWIIC devices connected. So far no fails.

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mikeysklar
 
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Re: SH1107

Post by mikeysklar »

3v is on the low side, but probably not the culprit.

Good to know the SH1107 appears stable on its own.

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kenidowa
 
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Re: SH1107

Post by kenidowa »

An update.
I am running the SH1107 in a slightly different configuration.
Feather-AHT20-PCF8523-SH1107(left input QWIIC connector). So far after ~24 hrs. and over 15,000 cycles there have been no Blanking screen failures on the SH1107. I am going to let this run for another 8-10 hrs. (overnight) then if still looks good try another configuration.
Any thoughts?

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mikeysklar
 
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Re: SH1107

Post by mikeysklar »

Well it will be interesting to see if just changing the order on the i2c chain has an effect. Honestly that is a surprise if it comes down to device order. It also means devices were unplugged/replugged which could have also changed the connection quality.

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kenidowa
 
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Re: SH1107

Post by kenidowa »

Well it failed after about 18000 cycles and more than 24 hrs.

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