A custom Pi Radio Bonnet is included in this project. The PCB features the SI4731-D60-GM IC, an AM/FM Broadcast Radio Receiver with RDS/RBDS. The reference clock is provided from the Pi through a hardware clock capable GPIO, and the I2C interface is used to control the functionality.
Besides the radio receiver, the PCB also features two units of the MAX98357A 3W PCM Amplifier, providing high quality stereo output.
The I2S audio interface is used for all devices, where the Pi acts as the master device reading digital audio from the radio receiver through the I2S_DIN line, and providing digital audio data to the amplifiers through the I2S_DOUT line.