128x32 random pixels of "snow"

[gnbl]

Hi,

I'm using PlatformIO with an ATtiny85@16.5 MHz (digispark clone) and Arduino / ATTinyCore (for SPI.h) with a generic 128x32 OLED module, that works with U8X8 (tinyd core). Using the following code, the display is correctly detected, but I only get random pixels on the display instead of "Hello".

; bitbank2/BitBang_I2C @ ^2.1.5 ; bitbank2/OneBitDisplay @ ^1.11.0

#include <BitBang_I2C.h>
#include <OneBitDisplay.h>
OBDISP obd;

void setup()
{

  int r = obdI2CInit(&obd, 
    OLED_128x32, 0,//0x3C, 
    0, 0, 
    0, 
    0xB2, // PB2
    0xB0, // PB0
    -1, 
    400000L);

  if(r<0) 
    digitalWrite(LED, HIGH);
  else{
    obdWriteString(&obd, 0,0,0, (char *)"Hello", FONT_NORMAL, 0, 1);
    digitalWrite(LED, HIGH);
    delay(100);
    digitalWrite(LED, LOW);
  }

  while(1);
}

Any guesses where things could be going wrong?

[gnbl]

Actually, it seems it does not detect the display.

[gnbl]

I2CTest() looks like it returns 0 for __AVR_ATtiny85__ without even trying ;-) It's also run twice in obdI2CInit() for some reason. Afterwards, whatever is being sent, it's not the initialization data :-( I'd try the tinyd core, but OBD requires also for the bit-bang I2C display..

[bitbank2]

The init function doesn't clear the display memory. Use obdFill() to clear it after initialization.