2.7" Monochrome OLED displays scrambled garbage and can't be

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trial_in_error
 
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2.7" Monochrome OLED displays scrambled garbage and can't be

Post by trial_in_error »

Hi!

I've got a HUZZAH32 and this 128x64 OLED (https://learn.adafruit.com/2-7-monochro ... e/assembly) and can't get the OLED to run the SSD1325 test program.

The display always looks like the last image in this user's thread (viewtopic.php?f=47&t=82868&p=419150&hil ... 25#p419150); roughly 50-50 lit and unlit pixels, with the lit pixels varying in intensity. I can invert the display, but not clear it or draw to it.

I've tried changing the display size in Adafruit_SSD1325.h to 128x32 to see if it helped; it did not. I've tried hardware & software SPI, and they perform identically.

Because I'm driving it from the HUZZAH32 (3.3v logic), there's no level shifter involved.

It shipped to me with the resistors in SPI mode, and a continuity check across each of them works fine.

I've rewired it & re-soldered it several times with no success and will attach images shortly.

Any clues or leads?

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Franklin97355
 
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Joined: Mon Apr 21, 2008 2:33 pm

Re: 2.7" Monochrome OLED displays scrambled garbage and can'

Post by Franklin97355 »

Can you post a picture of your boards and the connections between them?

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trial_in_error
 
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Re: 2.7" Monochrome OLED displays scrambled garbage and can'

Post by trial_in_error »

Sure!

Couple things to note:
- pull up 10k resistors (I hope) on pins 7, 8, and 16 of the display (SPI Clock, SPI DIN/MOSI, RESET)
- capacitor installed as per notes on adafruit learn page for the display
- intentionally avoided huzzah32 pins A2 and A3, because they're noted as input only
- software is set up for hardware SPI (so MOSI on pin 18, SPI Clock on pin 5)

Relevant software setup (rest is ssd1325test):

Code: Select all

// These are needed for both hardware & software SPI
#define OLED_CS 4
#define OLED_RESET 14
#define OLED_DC 36

// this is for hardware SPI, fast! but fixed oubs
Adafruit_SSD1325 display(OLED_DC, OLED_RESET, OLED_CS);
Breadboard, overview:
https://drive.google.com/open?id=0B7qS3 ... VWVDk4TVBF

Breadboard, closeup:
https://drive.google.com/open?id=0B7qS3 ... V5b0xWVFpV

Solder, front:
https://drive.google.com/open?id=0B7qS3 ... l4Q2xscG5V

Solder, back:
https://drive.google.com/open?id=0B7qS3 ... hlWExQQVI0

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adafruit2
 
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Joined: Fri Mar 11, 2005 7:36 pm

Re: 2.7" Monochrome OLED displays scrambled garbage and can'

Post by adafruit2 »

if you can invert the display then its at least sorta working - and getting commands. but ESP32 is really hard to debug, it also has pretty fast GPIO. can you try it with an UNO or Metro or other well-known and slower chip?

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trial_in_error
 
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Joined: Tue Aug 21, 2018 5:24 pm

Re: 2.7" Monochrome OLED displays scrambled garbage and can'

Post by trial_in_error »

So, moved from the Huzzah32 to a NodeMCU/ESP8266, and it's working fine! What can I expect to be less likely to work correctly with a Huzzah32? Are there any general rules, or will I have to trial & error per component? :/

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adafruit2
 
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Joined: Fri Mar 11, 2005 7:36 pm

Re: 2.7" Monochrome OLED displays scrambled garbage and can'

Post by adafruit2 »

esp32 is particularly weird - its not rare for things to not work on it, that's why we warn people :/ we know the OLED works for sure on arduino and compatibles.

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STETRO
 
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Joined: Thu Nov 08, 2018 9:19 am

Re: 2.7" Monochrome OLED displays scrambled garbage and can'

Post by STETRO »

hi,
"#define OLED_DC 36" this is an analog input A4 and also GPI #36. Note it is not an output-capable pin! It uses ADC #1
you must change pin ( GPI 21 for exemple)

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smp
 
Posts: 52
Joined: Tue Dec 18, 2018 4:40 pm

Re: 2.7" Monochrome OLED displays scrambled garbage and can'

Post by smp »

Hi,

Check out this thread:
viewtopic.php?f=22&t=89326&p=752588#p752588

I believe the "Another thread" that suggested 10k pull-ups was you!
Anyways, I digress...

My board uses the SAMD51, and I know nothing about the ESP32, but perhaps
its a drive current issue for you also. Research whether the ESP32 has control bits
allowing you to increase the drive. If not, try using a bus buffer/line driver chip
between the mcu and the SSD1325.

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