Tauno Erik
Published © GPL3+

FM Radio with Frequency Display

A simple FM radio with a display that shows the frequency and audio amplifier.

IntermediateShowcase (no instructions)10 hours9,216
FM Radio with Frequency Display

Things used in this project

Hardware components

Arduino Nano R3
Arduino Nano R3
×1
RDA5807M
×1
LM386
×1
MAX7219
×1
7 segment LED
×4

Software apps and online services

Arduino IDE
Arduino IDE

Story

Read more

Code

RDA5807M_radio_max7219.ino

Arduino
Full code
/* 
 *
 *  Find RDA5807M code at: https://github.com/lucsmall/Arduino-RDA5807M
 *
 *  "Talking about my Arduino sketch for the RDA5807M FM Radio IC"
 *  http://youtu.be/9TegkAu96nE
 *
 *  "Connecting the RDA5807M FM Radio IC to an Arduino"
 *  https://youtu.be/2j1hX4uzkQ8
 *
 *  "Making my Arduino controlled RDA5807M FM Radio"
 *  https://youtu.be/4pZmkeqg5h8
 */

#include <Wire.h>

#define MAX7219_DIN 12
#define MAX7219_CS  10
#define MAX7219_CLK 11

/* Rotary Encoder: */
/*
const int clkPin = 5;   // clk - pin 5
const int dtPin  = 6;   //  dt - pin 6
const int swPin  = 2 ;  //  sw - pin 2
*/

#define clkPin 5   // clk - pin 5
#define dtPin  6   //  dt - pin 6
#define swPin  2  //  sw - pin 2



    /* Select the frequency we want to tune to by way
     * of selecting the channel for the desired frequency 
     */
uint16_t channel = 191; 
    /*
     * assuming band starts at 87.0MHz (per settings below)
     * and channel spacing of 100kHz (0.1MHz) (per settings below)
     * then channel can be derived as follows:
     *  
     * channel = (<desired freq in MHz> - 87.0) / 0.1 
     *
     * which is the same as:
     * <10 x desired freq in MHz> - 870
     *   
     *  some examples:
     * channel 145 dec = 101.5 MHz
     * channel 153 dec = 102.3 MHz
     * channel 177 dec = 104.7 MHz
     * channel 193 dec = 106.3 MHz
     * channel 209 dec = 107.9 MHz
     * 191 = 106.1 Vikerraadio
     * 187 = 105.7 Klassika raadio
     */

/* address of the RDA5807 on two wire bus */
#define RDA5807M_ADDRESS  0b0010000 // 0x10

#define BOOT_CONFIG_LEN 12
#define TUNE_CONFIG_LEN 4

/* 
 *  These bytes set our initial configuration
 *  We don't bother to tune to a channel at this stage.
 *  But instead initiate a reset.
 */
uint8_t boot_config[] = {
  /* register 0x02 */
  0b11000000,
    /* 
     * DHIZ audio output high-z disable
     * 1 = normal operation
     *
     * DMUTE mute disable 
     * 1 = normal operation
     *
     * MONO mono select
     * 0 = stereo
     *
     * BASS bass boost
     * 0 = disabled
     *
     * RCLK NON-CALIBRATE MODE 
     * 0 = RCLK is always supplied
     *
     * RCLK DIRECT INPUT MODE 
     * 0 = ??? not certain what this does
     *
     * SEEKUP
     * 0 = seek in down direction
     *
     * SEEK
     * 0 = disable / stop seek (i.e. don't seek)
     */
  0b00000011,
    /* 
     * SKMODE seek mode: 
     * 0 = wrap at upper or lower band limit and contiue seeking
     *
     * CLK_MODE clock mode
     *  000 = 32.768kHZ clock rate (match the watch cystal on the module) 
     *
     * RDS_EN radio data system enable
     * 0 = disable radio data system
     *
     * NEW_METHOD use new demodulate method for improved sensitivity
     * 0 = presumably disabled 
     *
     * SOFT_RESET
     * 1 = perform a reset
     *
     * ENABLE power up enable: 
     * 1 = enabled
     */ 

  /* register 0x03 */
    /* Don't bother to tune to a channel at this stage*/
  0b00000000, 
    /* 
     * CHAN channel select 8 most significant bits of 10 in total
     * 0000 0000 = don't boher to program a channel at this time
     */

  0b00000000,
    /* 
     * CHAN two least significant bits of 10 in total 
     * 00 = don't bother to program a channel at this time
     *
     * DIRECT MODE used only when test
     * 0 = presumably disabled
     *
     * TUNE commence tune operation 
     * 0 = disable (i.e. don't tune to selected channel)
     *
     * BAND band select
     * 00 = select the 87-108MHz band
     *
     * SPACE channel spacing
     * 00 = select spacing of 100kHz between channels
     */
     
  /* register 0x04 */
  0b00001010, 
    /* 
     * RESERVED 15
     * 0
     *
     * PRESUMABLY RESERVED 14
     * 0
     *
     * RESERVED 13:12
     * 00
     *
     * DE de-emphasis: 
     * 1 = 50us de-emphasis as used in Australia
     *
     * RESERVED
     * 0
     *
     * SOFTMUTE_EN
     * 1 = soft mute enabled
     *
     * AFCD AFC disable
     * 0 = AFC enabled
     */
  0b00000000, 
    /* 
     *  Bits 7-0 are not specified, so assume all 0's
     * 0000 0000
     */
  
  /* register 0x05 */
  0b10001000, 
    /* 
     * INT_MODE
     * 1 = interrupt last until read reg 0x0C
     *
     * RESERVED 14:12 
     * 000
     *
     * SEEKTH seek signal to noise ratio threshold
     * 1000 = suggested default
     */ 
  
  0b00001111, 
    /* 
     * PRESUMABLY RESERVED 7:6
     * 00
     *
     * RESERVED 5:4
     * 00
     *
     * VOLUME
     * 1111 = loudest volume
     */
  
  /* register 0x06 */
  0b00000000, 
    /* 
     * RESERVED 15
     * 0
     *
     * OPEN_MODE open reserved registers mode
     * 00 = suggested default
     *
     * Bits 12:8 are not specified, so assume all 0's
     * 00000
     */ 
   
  0b00000000, 
    /* 
     *  Bits 7:0 are not specified, so assume all 0's
     *  00000000
     */
    
  /* register 0x07 */
  0b01000010, 
    /* 
     *  RESERVED 15 
     * 0
     *
     * TH_SOFRBLEND threshhold for noise soft blend setting
     * 10000 = using default value
     *
     * 65M_50M MODE 
     * 1 = only applies to BAND setting of 0b11, so could probably use 0 here too
     *
     * RESERVED 8
     * 0
     */    
  
  0b00000010, 
    /*   
     *  SEEK_TH_OLD seek threshold for old seek mode
     * 000000
     *
     * SOFTBLEND_EN soft blend enable
     * 1 = using default value
     *
     * FREQ_MODE
     * 0 = using defualt value
     */  
};

/* After reset, we can tune the device
 * We only need program the first 4 bytes in order to do this
 */
uint8_t tune_config[] = {
  /* register 0x02 */
  0b11000000, 
    /* 
     * DHIZ audio output high-z disable
     * 1 = normal operation
     *
     * DMUTE mute disable 
     * 1 = normal operation
     *
     * MONO mono select
     * 0 = stereo
     *
     * BASS bass boost
     * 0 = disabled
     *
     * RCLK NON-CALIBRATE MODE 
     * 0 = RCLK is always supplied
     *
     * RCLK DIRECT INPUT MODE 
     * 0 = ??? not certain what this does
     *
     * SEEKUP
     * 0 = seek in down direction
     *
     * SEEK
     * 0 = disable / stop seek (i.e. don't seek)
     */
    
   0b00000001, 
    /* 
     * SKMODE seek mode: 
     * 0 = wrap at upper or lower band limit and contiue seeking
     *
     * CLK_MODE clock mode
     * 000 = 32.768kHZ clock rate (match the watch cystal on the module) 
     *
     * RDS_EN radio data system enable
     * 0 = disable radio data system
     *
     * NEW_METHOD use new demodulate method for improved sensitivity
     * 0 = presumably disabled 
     *
     * SOFT_RESET
     * 0 = don't reset this time around
     *
     * ENABLE power up enable: 
     * 1 = enabled
     */ 

   /* register 0x03 */
   /* Here's where we set the frequency we want to tune to */
   (channel >> 2), 
    /* CHAN channel select 8 most significant bits of 10 in total   */

   ((channel & 0b11) << 6 ) | 0b00010000
    /* 
     *  CHAN two least significant bits of 10 in total 
     *
     * DIRECT MODE used only when test
     * 0 = presumably disabled
     *
     * TUNE commence tune operation 
     * 1 = enable (i.e. tune to selected channel)
     *
     * BAND band select
     * 00 = select the 87-108MHz band
     *
     * SPACE channel spacing
     * 00 = select spacing of 100kHz between channels
     */  
};



void setup()
{
  Serial.begin(9600);
  
  /* Rotary Encoder: */
  pinMode(clkPin, INPUT);
  pinMode(dtPin, INPUT);
  pinMode(swPin, INPUT); 
  digitalWrite(swPin, HIGH);

  
  /* Conect to RDA5807M FM Tuner: */
  Wire.begin(); /* join i2c bus (address optional for master) */
  
  Wire.beginTransmission(RDA5807M_ADDRESS); /* Sending boot configuration (device should reset) */
  Wire.write(boot_config, BOOT_CONFIG_LEN); /* Write the boot configuration bytes to the RDA5807M */
  Wire.endTransmission();
  
  Wire.beginTransmission(RDA5807M_ADDRESS); /* Tuning to channel */
  Wire.write(tune_config, TUNE_CONFIG_LEN); /* Write the tuning configuration bytes to the RDA5807M */
  Wire.endTransmission(); 


   // put your setup code here, to run once:
   
  initialise();
  output(0x0f, 0x00); //display test register - test mode off
  output(0x0c, 0x01); //shutdown register - normal operation
  output(0x0b, 0x07); //scan limit register - display digits 0 thru 7
  output(0x0a, 0x0f); //intensity register - max brightness
  output(0x09, 0xff); //decode mode register - CodeB decode all digits
  output(0x08, 0x0c); //digit 7 (leftmost digit) data
  output(0x07, 0x0b);
  output(0x06, 0x0d);
  output(0x05, 0x0e);
  output(0x04, 0x08);
  output(0x03, 0x07);
  output(0x02, 0x06);
  output(0x01, 0x05); //digit 0 (rightmost digit) data
  
  
}//setup end

void loop()
{
  /* Read Rotary Encoder: */
  int change = getEncoderTurn();

  if (change > 0){
    channel++;
    myChangeChannel(channel);
    }
  else if(change < 0){
    channel--;
    myChangeChannel(channel);
    }

  /* Rotary Encoder Button: */
  if(digitalRead(swPin) == LOW) //if button pull down
  {
    /* tee midagi kui nuppu vajutatud 
       salvesta niteks sagedus mllu!
       */
  }

  uint16_t frequency = channel+870;

  uint16_t num1 = (frequency / 1000) % 10;
  uint16_t num2 = (frequency / 100) % 10;
  uint16_t num3 = (frequency / 10) % 10;
  uint16_t num4 = frequency % 10;

  Serial.print(num1);
  Serial.print(num2);
  Serial.print(num3);
  Serial.print(num4);
  Serial.print("--");
  Serial.println(channel+870);
  

  // put your main code here, to run repeatedly: 
  
  output(0x01, num1);
  output(0x02, num2);
  output(0x03, num3);
  output(0x04, num4);
  
  
  //delay(100);
  
}//loop end

/*
 * Function to read Rotary Encoder turn:
 * left or right
 * Returns: 1 or -1
 */
int getEncoderTurn(void)
{
  static int oldA = HIGH; // set the oldA as HIGH
  static int oldB = HIGH; // set the oldB as HIGH
  int result = 0;
  int newA = digitalRead(clkPin);   // read the value of clkPin to newA
  int newB = digitalRead(dtPin);    // read the value of dtPin to newB
  
  if (newA != oldA || newB != oldB) // if the value of clkPin or the dtPin has changed
  {
    /* something has changed */
    if (oldA == HIGH && newA == LOW)
    {
      result = (oldB * 2 - 1);
      /* Serial.print("Result: ");
         Serial.println(result); */
    }
  }
  oldA = newA;
  oldB = newB;
  
  return result; // 1 or -1
}


/*
 * Function to change channel on radio RDA5807
 * Example: channel = 191 
 */
void myChangeChannel(int channel){ /* void if nothing is returned else int */
  /*
   * first write new channel to tune_config massive
   */
   tune_config[2] = (channel >> 2); 
   tune_config[3] = ((channel & 0b11) << 6 ) | 0b00010000;
      
      Wire.begin();
      Wire.beginTransmission(RDA5807M_ADDRESS);
      Wire.write(tune_config, TUNE_CONFIG_LEN);
      Wire.endTransmission();
  }

/*
 * Function to initialise MAX7219 7-segment LED display
 */
void initialise()
{
  digitalWrite(MAX7219_CS, HIGH);
  pinMode(MAX7219_DIN, OUTPUT);
  pinMode(MAX7219_CS, OUTPUT);
  pinMode(MAX7219_CLK, OUTPUT);
}

/*
 * Function to send data to MAX7219 7-segment LED display
 */
void output(byte address, byte data)
{
  digitalWrite(MAX7219_CS, LOW);
  shiftOut(MAX7219_DIN, MAX7219_CLK, MSBFIRST, address);
  shiftOut(MAX7219_DIN, MAX7219_CLK, MSBFIRST, data);
  digitalWrite(MAX7219_CS, HIGH);
}

 

Credits

Tauno Erik

Tauno Erik

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