Adafruit_SH1106G not working on SPI

[gps79]

• Arduino board: NodeMCU v3

• Arduino IDE version (found in Arduino -> About Arduino menu): 1.8.15

• List the steps to reproduce the problem below (if possible attach a sketch or copy the sketch code in too): LIST REPRO STEPS BELOW

  1. Build and run example https://github.com/adafruit/Adafruit_SH110x/blob/master/examples/OLED_QTPY_SH1106/SH1106_128x64_SPi_QTPY/SH1106_128x64_SPi_QTPY.ino

Expected result: Software runs without errors.

Actual result: Software crashes.

Root cause:

• file: Adafruit_SH110X.cpp
• method: void Adafruit_SH110X::display(void)
• line: uint16_t maxbuff = i2c_dev->maxBufferSize() - 1;
• cause: i2c_dev is null for SPI connection

[ladyada]

are you using adafruit hardware? if so please post a photo!

[gps79]

I don't use adafruit hardware. I just pointed an error (i2c_dev is a null pointer and causes crash). The fix for that is to move line: uint16_t maxbuff = i2c_dev->maxBufferSize() - 1; below line: if (i2c_dev) { // I2C

so it's executed only when i2c_dev structure is initialized. Then the SW doesn't crash.

[caternuson]

What code are you running? Is it calling begin() on the display instance?

EDIT - oh, this is for SPI usage. OK, seeing it now. For the SPI case, i2c_dev never gets init'd: https://github.com/adafruit/Adafruit-GFX-Library/blob/4a33fcd467e373d1eedd3aef6f5f9be36f5c276b/Adafruit_GrayOLED.cpp#L242-L252 so the call to display() will try to access a null pointer here: https://github.com/adafruit/Adafruit_SH110x/blob/2f7d9fbdc6596d449d303bd7d8b44399012a27de/Adafruit_SH110X.cpp#L170

[caternuson]

@gps79 If you can, please test the changes in PR #11.

[gps79]

It's working fine with your fix. No more crashes. Thank you.