OLED on a different i2c than i2c_1

Troubleshooting and Support
1

hey,
I have i2c_1 already in use with the mpr121, so I want to run the oled on different ports. It works fine with the standard ports from the example, but no combination I tried works for other ports.

also running the oled as slave with adress 0x3D on i2c_1 is not working.
it´s the 1.3 inch azdelivery oled.

this is what I try:
I have the sdk and sda connected to the two ports above what is stated as 8 and 9 in the example, so this should be 10 and 11 and it shows as i2c_4 in the pinout.

 /** Configure the Display */
    MyOledDisplay::Config disp_cfg;
    disp_cfg.driver_config.transport_config.i2c_address               = 0x3C;
    disp_cfg.driver_config.transport_config.i2c_config.periph         = I2CHandle::Config::Peripheral::I2C_4;
    disp_cfg.driver_config.transport_config.i2c_config.speed          = I2CHandle::Config::Speed::I2C_100KHZ;
    disp_cfg.driver_config.transport_config.i2c_config.mode           = I2CHandle::Config::Mode::I2C_MASTER;
    disp_cfg.driver_config.transport_config.i2c_config.pin_config.scl = {DSY_GPIOB, 10};    
    disp_cfg.driver_config.transport_config.i2c_config.pin_config.sda = {DSY_GPIOB, 11};
2

Ok, so I solved this by putting the oled on the same bus like the mpr121,
and for good measure added the line

mprConfig.transport_config.mode  = I2CHandle::Config::Mode::I2C_SLAVE;

to the mpr config

now my audio is slowed down significantly, even though I write the oled very slowly.

how do you get your oled running without it slowing down everything?

3

This doesn’t make sense to me. This configuration is used to set up the Daisy’s I2C port. The Daisy is the MASTER, the MPR is SLAVE.

mprConfig.transport_config.mode = I2CHandle::Config::Mode::I2C_SLAVE;

4

Sorry I don‘t understand
-the mpr usually ran as master, worked
-now the oled is master, the mpr is slave, works.

should both be set to slave or does this setting not even matter?

but trying to use another i2c bus (the two ports above are marked as i2c_4 and therefore should work with pins 10, 11. does not work with the oled.

5

I suggest you read about I2C. It is a bus system where there is one master, and one or more slaves.

The OLED and MPR can only operate as SLAVE. The Daisy can be configured to act as either the MASTER or SLAVE.

Perhaps this can help you understand:
I2C tutorial.

I have not read that, but I looked quickly, and it appears to explain I2C.