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technoblogy / tiny-i2c

Minimal I2C master routines for all AVR microcontrollers.
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ATiny406 compatibility #18

Closed laserranger3000 closed 2 months ago

laserranger3000 commented 2 months ago

I'm trying to use this library to communicate with a MAX30102 sensor with an ATiny406. There is a project that implements just that on an ATiny85: https://github.com/jeffmer/tinyPulsePPG

However, I can't get it to run on my microcontroller. As soon as the MAX30102 driver runs TinyI2C.start, the whole program freezes.

It's not a hardware problem, since using the Arduino wire library works just fine. I just can't use it due to the high amount of RAM it requires.

Is there any reason why it wouldn't run on an 406?

technoblogy commented 2 months ago

It should certainly work with the ATtiny406. Have you rewritten the I2C commands to suit the TinyI2C library? The way the commands work is a bit different from Arduino Wire. I assume you've called TinyI2C.init()?

laserranger3000 commented 2 months ago

Yes, I've called the init function.

I finally got it to work by adding 5ms delay after the init function:

//MAX30102
TinyI2C.init();
_delay_ms(5);
sensor.begin();
sensor.setup();

Also, the MAX30102 library had one delay() call that I have missed, by changing that to _delay_ms() it works flawlessly. I'm not sure why the 5ms delay is required. It was trial&error.

technoblogy commented 2 months ago

Glad you got it working!