NAU881x audio codec library for STM32

Work in progress and untested

Compatible with Nuvoton NAU8810, NAU88C10, NAU8814, and NAU88C14 mono audio codecs. Specific NAU8814 (and NAU88C14) features are prefixed by NAU8814_. It might be compatible with NAU8812

Useful links:

• Product page: NAU8810 NAU88C10 NAU8814 NAU88C14
• Datasheet: NAU8810 NAU8812 NAU8814

How to use

Write your implementation to write/read register from the device. For example:

// --- main.c ---

void MyI2C_Write(I2C_HandleTypeDef* i2c_handle, uint8_t i2c_address, uint8_t register, uint16_t value)
{
    uint8_t data[] = {register, value >> 8, value & 0xFF};
    HAL_I2C_Master_Transmit(i2c_handle, i2c_address, data, sizeof(data), HAL_MAX_DELAY);
}

uint16_t MyI2C_Read(I2C_HandleTypeDef* i2c_handle, uint8_t i2c_address, uint8_t register)
{
    uint16_t value = 0;
    HAL_I2C_Master_Transmit(i2c_handle, i2c_address, &register, 1, HAL_MAX_DELAY);
    HAL_I2C_Master_Receive(i2c_handle, i2c_address, &value, 2, HAL_MAX_DELAY);
    return value;
}

// --- main.h ---

void MyI2C_Write(I2C_HandleTypeDef* i2c_handle, uint8_t i2c_address, uint8_t register, uint16_t value);
uint16_t MyI2C_Read(I2C_HandleTypeDef* i2c_handle, uint8_t i2c_address, uint8_t register);

Edit the nau881x.h to call your implementation

// --- nau881x.h ---

#include "main.h"    // The location of the function prototype for the implementation

#define NAU881X_REG_WRITE(handle, reg, val) MyI2C_Write(handle, NAU8810_I2C_ADDRESS, reg, val)
#define NAU881X_REG_READ(handle, reg) MyI2C_Read(handle, NAU8810_I2C_ADDRESS, reg)

Now you can initialize the audio codec, configure the Digital Audio Interface to transmit/receive audio data, and follow the audio path from the Block Diagram section in the datasheet.

// --- main.c ---

#include "nau881x.h"

NAU881x_t nau8810;

int main(void)
{
    // ...

    nau8810.comm_handle = &hi2c1;
    NAU881x_Init(&nau8810);

    // STM32 as I2S Master
    // TODO

    // Make audio codec functional
    // Code below will route the audio from MICN to Speaker via Bypass (refer to General Block Diagram)
    NAU881x_Set_PGA_Input(&nau8810, NAU881X_INPUT_MICN);
    NAU881x_Set_Speaker_Source(&nau8810, NAU881X_OUTPUT_FROM_BYPASS);
    NAU881x_Set_Output_Enable(&nau8810, NAU881X_OUTPUT_SPK);

    // ...
}

Implemented (based on functional description):

• Input path
  • Single ended auxiliary input (AUX) (NAU8814)
  • Differential microphone input
  • PGA boost/Mixer stage
• Microphone biasing
• ADC digital filter
  • ADC
  • High pass filter
  • Notch filter
  • ADC gain
• Programmable gain amplifier (PGA)
  • Automatic level control (ALC)
• DAC digital filter
  • DAC
  • 5-band equalizer
• Analog outputs
  • Speaker mixer
  • Mono mixer
• General purpose control
  • Slow timer clock
  • Jack detect (NAU8814)
  • Thermal shutdown (NAU8814)
• Clock generation
• Control interface
  • Control interface selection (NAU8814)
• Digital audio interface
  • Interface modes
  • Companding
• Power supply
  • Power up sequence