No activity on Attiny85

[oomek]

I've started experimenting with your library today, but so far I haven't managed to get any output, even as simple code as this does not show any activity on the logic analyzer.

#include <Arduino.h>
#include <BitBang_I2C.h>

BBI2C bbi2c;
uint8_t test[4] = {1,2,3,4};

void setup()
{
    memset(&bbi2c, 0, sizeof(bbi2c));
    bbi2c.bWire = 0;
    bbi2c.iSDA = PB0;
    bbi2c.iSCL = PB2;
    I2CInit(&bbi2c, 400000L);
    delay(100);
}

void loop()
{
    // This works
    // pinMode(PB0, OUTPUT);
    // pinMode(PB2, INPUT);
    // delay(100);
    // pinMode(PB0, INPUT);
    // pinMode(PB2, OUTPUT);

    // This does not
    I2CWrite(&bbi2c, 0x46, test, 4);
    delay(1000);
}

Am I doing something wrong?

[bitbank2]

As it says in the readme, you need to specify the pin numbers differently for AVR to use the fast code. PB0 should be passed as 0xB0 PB2 should be passed as 0xB2

[oomek]

Sorry, I must have missed that. The waveform looks nice, although the PWM is very wide in low speeds. I've had to set I2CInit(&bbi2c, 1600000L); to get 400kHz on Attiny85 btw.

[bitbank2]

I wasn't accurate with the timing because this library was really aimed at pushing the SSD1306 to go as fast as possible. Most I2C devices are pretty forgiving with the waveform shape and timing.