Please help me to identify OLED 0.91 display - Page 1
Forum section: electronics / beginners

author: sairfan1
author_rank: Frequent Contributor
timestamp: September 26, 2022, 05:43:21 pm
content: I'm using a sketch that loops through all possible I2C addresses but modules does not respond to any I2C address, There is an open jumper or resistor pads (R5) on the back of PCB not sure if its used to configure I2C address, this modules is a bit different than other commonly available OLED 128x32 displays which worked right away.Pictures are attached.

author: MikeK
author_rank: Super Contributor
timestamp: September 26, 2022, 05:53:35 pm
content: I have several of the same displays. No jumper at R5. They're all addressed as 0x78, which is 0x3C moved over to the correct place. The problem is likely in your code.

author: sairfan1
author_rank: Frequent Contributor
timestamp: September 26, 2022, 08:02:31 pm
content: What code or library are you using to test it,? i have few of them without R5 pads on them and they work all good, this one is a bit different with R5 pads and i was not able to receive any response from it.Same code i used to communicate with other modules and they work all good.

author: MikeK
author_rank: Super Contributor
timestamp: September 26, 2022, 08:22:19 pm
content: I have used several different PIC's and my own code. What method/device are you using to communicate with it?

author: MikeK
author_rank: Super Contributor
timestamp: September 26, 2022, 08:37:30 pm
content: Does "sketch" mean that you're using an Arduino?

author: sairfan1
author_rank: Frequent Contributor
timestamp: September 26, 2022, 09:09:36 pm
content: Yes I'm using arduino, code worked for other OLED displays but not this one, and i noticed that its a little bit different with R5 pads.

author: MikeK
author_rank: Super Contributor
timestamp: September 26, 2022, 10:20:04 pm
content: Any code that works for a 128x64 I2C OLED will work for your 128x32 OLD, with the exception that the display will be garbled.But the test is useful. If you have a 128x64, write a sketch that displays something on each line (page). Then swap in the 128x32. It should display a garbled mess. If nothing shows, your OLED may be faulty.

author: MikeK
author_rank: Super Contributor
timestamp: September 26, 2022, 11:35:56 pm
content: This worked for me, with the same display as yours.https://startingelectronics.org/tutorials/arduino/modules/OLED-128x32-I2C-display/

author: kjr18
author_rank: Regular Contributor
timestamp: September 27, 2022, 11:10:55 am
content: Have you tried i2c_scanner sketch? It should show every device connected to bus. Maybe data pins are mislabelled and swapping those would help?

author: sairfan1
author_rank: Frequent Contributor
timestamp: September 27, 2022, 03:52:16 pm
content: QuoteYes I tried scanner sketch, but did not find any device on I2C bus, that's why i was thinking may be I have to set address jumpers.

author: tooki
author_rank: Super Contributor
timestamp: September 27, 2022, 04:00:33 pm
content: I think some of these OLEDs use a jumper to configure between I2C and SPI.And of course there’s always the possibility that it’s simply faulty.

author: iMo
author_rank: Super Contributor
timestamp: September 27, 2022, 04:10:42 pm
content: Mind you would need two pull-up resistors (1k-10k based on required clock speed) on the I2C bus..

author: sairfan1
author_rank: Frequent Contributor
timestamp: September 27, 2022, 05:01:40 pm
content: QuotePull up resistors are present on the PCB, I believe there is something to configure I2C address or this module is not working at all.

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 27, 2022, 10:56:10 pm
content: Check voltage at C9, if not 3.3V then power the display with 5V, Q1 is a 3.3V regulator.What library are you using?Some decent pictures: