Simple FM Radio using TEA5767 Module

Introduction

The TEA5767 is a single-chip electronically tuned FM stereo radio module for low-voltage applications with fully integrated Intermediate Frequency (IF) selectivity and- demodulation. The radio is completely adjustment-free and only requires a very few external components. The digital tuning is based on the conventional PLL concept. The power consumption of the tuner is low. The current is about 13mA and the supply voltage can be varied between 2.5 and 5V.

It has a frequency range of between 76 and 108MHz. You can use Arduino to drive this module.

The TEA5767 chip itself is a 40-pin package. The module I have has the chip mounted on a small PCB with most of the required supporting components. It exposes only 10 pins:

Pin	Name	Description
1	SDA	I²C data
2	SCL	I²C clock
3	BUSMODE	bus mode select input
4	W/R	write/read control input for the 3-wire bus
5	VCC	2.5-5V
6	GND	ground
7	ROUT	right audio out
8	LOUT	left audio out
9	MPXO	FM demodulator MPX signal output
10	ANT	antenna in

Schematic Diagram

Refer the image below. On the left we have the IC2 connections SDA and SCL that will go to pins A5 and A4 respectively on the Arduino Uno.

The right hand side has a connection ANT (antenna) left and right audio and ground.

Arduino Code

/*

  FM/TEA5767
  Control the TEA5767 low-power FM stereo radio chip with an Arduino.

  For info and circuit diagrams see https://github.com/tardate/LittleArduinoProjects/tree/master/Radio/FM/TEA5767

 */

#include <Wire.h>

// a sampling of India radio stations..
const double STATIONS[] = {
  91.5, 
  93.5, 
  98.3,
  105.0
};

const double SAMPLE_DELAY = 2000;

void setup() {
  Serial.begin(9600);
  Wire.begin();
  delay(500);
}

void loop() {
  for(int station=0; station < sizeof(STATIONS) / sizeof(double); ++station) {
    setFrequency(STATIONS[station]);
    delay(SAMPLE_DELAY);
  }
}

void setFrequency(double frequency) {
  int frequencyB = 4 * (frequency * 1000000 + 225000) / 32768;
  byte frequencyH = frequencyB >> 8;
  byte frequencyL = frequencyB & 0xFF;

  Serial.print(F("Setting frequency "));
  Serial.println(frequency);
  Wire.beginTransmission(0x60);
  Wire.write(frequencyH & 0b00111111);
  Wire.write(frequencyL);
  Wire.write(0b10110000);
  Wire.write(0b00010000);
  Wire.write(0b00000000);
  Wire.endTransmission();
}
The above code is just sampling. This can be modified to take input from pot or push button. 

In my next post will show on how we can modify it to add display and frequency selector.