fooker / attiny85-i2c-pwm

I²C controleld PWM generator based on ATTiny85

ATTiny85 - I²C - PWM

This is a firmware for ATTiny85 microcontrollers providing a PWM signal controlled via I²C. The microcontroller acts as a I²C slave and allows a single byte write operation which is used unmodified as PWM output value.

Pins and Wiring

Beside the usual VCC andGND pins, the following pins are used:

• 5 (PB0) - I²C SDA
• 6 (PB1) - PWM output
• 7 (PB2) - I²C SCL

The I²C pins utilize the internal pull-ups but external pull-up resistors should be added according to the specifications.

Configuration

The configuration can be done by mondifying config.h accordin to the needs. Right now, there are only two options to set:

• TWI_ADDRESS - Contains the address of the slave on the I²C bus. This must only contain the leading 7 bit of the address without the R/W flag.
• PWM_PRESCALER - The prescaler to use for the PWM output. See Table 12-5 in the ATTiny85 datasheed vor valid values. All settings are relative to 8MHz CPU frequence.