Attiny3216 vs SSD1306 problem

[metehoca]

I designed a small board using the ATtiny3216 and MegaTinyCore, along with a 0.96" SSD1306 OLED display. I used 4.7K I2C pull-up resistors, just as I have in previous projects. However, I have a strange issue. The board works with the Adafruit SSD1306 library, but I can never get any display output with U8G2. Do you have any suggestions for a solution?

[olikraus]

Did you try SW_I2C constructor?

[metehoca]

Just tried these below with helloworld sketch, it did not work.

U8G2_SSD1306_128X64_NONAME_F_SW_I2C u8g2(U8G2_R0, /* clock=/ PIN_WIRE_SCL, / data=/ PIN_WIRE_SDA, / reset=/ U8X8_PIN_NONE);
U8G2_SSD1306_128X64_NONAME_F_SW_I2C u8g2(U8G2_R0, / clock=/ SCL, / data=/ SDA, / reset=*/ U8X8_PIN_NONE);

[metehoca]

Strange behavior: Uploading the Adafruit example works fine. Then, uploading the U8G2 example also works, but after a power cycle, the screen remains blank. However, the Adafruit example continues to work even after a power cycle.

It seems Adafruit initializes the display differently from U8G2. When the Adafruit configuration remains active, U8G2 also functions properly.

[olikraus]

Hmm indeed strange. Maybe calling u8g2.begin() twice could help. There are also some other SSD1306 constructor calls. Maybe one of the others will work better.

[metehoca]

I tried what you suggested, but I still couldn't get it to work. I'm sure this is a hardware issue because my first board on a protoboard works flawlessly with U8G2. However, I'm experiencing this issue on the PCB, even though everything is correctly prepared and follows the same schematic. It looks like we'll learn something once I figure it out. The fact that Adafruit, ss_oled, and ssd1306ascii work while U8G2 doesn't is quite confusing.

[olikraus]

hmm