Published December 30, 2022 © GPL3+

I2S output FM Tuner with RDS

I2S(Inter-IC Sound) output FM tuner using ESP-01 with RDS and IR remote control. 100% pure digital music output at upto 48ksps. Enjoy!

IntermediateProtip4 hours500

Things used in this project

Hardware components

Espressif ESP8266 ESP-01

DFRobot Monochrome 0.91”128x32 I2C OLED Display with Chip Pad

RDA Microelectronics RDA7088N

Resistor 10k ohm

32.768 kHz Crystal

Linear Regulator (Low Dropout)

AMS117 3.3V LDO

Micro-USB to USB Cable (Generic)

SparkFun Logic Level Converter - Bi-Directional

Infrared Receiver, 38 kHz

Itead PiFi DAC: I2S Interface HIFI DAC+ Sound Card For Raspberry PI

Capacitor 220 µF

SparkFun TRRS 3.5mm Jack Breakout

Male Header 40 Position 1 Row (0.1")

Female Header 8 Position 1 Row (0.1")

Female Header 20 Position 2 Row (0.1")

SparkFun USB Mini-B Breakout

Jumper wires (generic)

Female/Female Jumper Wires

Male/Female Jumper Wires

Male/Male Jumper Wires

Headphones, 18 Hz

Temperature Sensor IC, 256B EEPROM

AT24C02 or AT24C04

Software apps and online services

Arduino IDE

NodeMCU firmware

Microsoft Windows 10

Hand tools and fabrication machines

Soldering iron (generic)

Solder Wire, Lead Free

Solder Flux, Soldering

Soldering stand, With Sponge

Story

Compared to yesterday, more and more things are moving towards digital! If the FM tuner is capable of delivering 100% pure digital music then why we need to restrict ourselves still listening in Analog? Let's go digital!

I2S FM Tuner with RDS display and IR remote control using ESP-01

In this project we will learn how to implement IR remote controlled I2S(inter-IC sound bus) output FM tuner with Radio Data System (RDS) using ESP-01.

Timing diagram for the I2S lines, from the Philips specification document.

We are all familiar with RRD-102 V.2 module and connection. We are also familiar with many Arduino libraries available to control the RRD-102 V.2 module. Most of the Arduino libraries comes with RDS information display using LCD or OLED. There are many IR remote control libraries available. There are many OLED and LCD libraries available for graphical and text display.

I am not going to discuss any of the above in details here.

There are many FM Tuner family of ICs with I2S digital output available from Silabs, Quintic, RDA Microelectronics, etc.,

For DIY enthu the deciding factors are different. Simple foot-print for easy and quick prototyping using bread board, easily available, BOM Cost and circuit complexity(few external components)

RDA Microelectronics FM tuners mainly available in MSOP10, SOIC8, SOP16 and QFN packages. Most of the SOP16 and QFN comes with I2S digital output support.

Since the internal I2C bus address and register organization remains the same, we can use any of the RDA FM tuner Arduino Library and are compatible across family including 5802, 5820 series.

All the SOP16 and QFN package ICs comes with 3 GPIO pins. These GPIOs can be set to High, Low or used to Interrupt generation. Please refer to datasheet for more details.

The basic connection and software are exactly same as conventional wiring except very few minor changes.

Conventional FM tuner with I2C interface:

FM tuner with I2C interface using SOP16 package

In this project we will be controlling the I2C bus by using ESP-01.

ESP-01 pin map

GPI00 - SDA(FM tuner + OLED or LCD + EEPROM)
GPIO2 - SCL(FM tuner + OLED or LCD + EEPROM)
GPIO3 - Rx - IR receiver

The optional EEPROM can be added to the same I2C bus which can be used to store the previous state of the channel frequency and any other user preferred data or settings so that during next power ON the ESP-01 will load the settings from the EEPROM. We can emulate and implement the EEPROM using the FLASH MEMORY used by ESP-01. Just by adding external EEPROM we can improve the reliability of the FLASH MEMORY by avoiding frequent read/write cycle of FLASH unnecessarily.

The I2S bus has three signals:

continuous serial clock (SCK)
word select (WS)
serial data (SD)

FM Tuner with I2S(inter-IC sound bus) Digital output Audio Format

If we enable the I2S output of RDA FM tuner, then the following GPIO pins will be assigned to the I2S signals

PIN# 01 - GPIO1 - WS
PIN# 16 - GPIO2 - SD
PIN# 15 - GPIO3 - SCK

SOP16 pinout with GPIO1, GPIO2 and GPIO3

Even if we enable the I2S, still the analog output availabe on LOUT & ROUT pins concurrently!

To Enable the I2S output we need to set only 3 bits to "1".

REGister 04H bit#6 I2S_ENABLE = "1"
REGister 06H bit#9 data_signed = "1"
REGister 06H bits[7:4] I2S_SW_CNT[4:0] - 4'b1000 for 48kbps

The default audio sample rate is 8ksps. User should select REGister 0x06H bits to select the higher sampling rate. Please refer to the CODE section for REGister 0x04H and REGister 0x06H details.

After enabling the above 3 bits, the GPIOs will output the I2S signals. We can directly connect these three pins to any suitable I2S Audio DAC.

You can refer to any of the SOP16 or QFN package RDA FM tuner datasheet for more register and programming options.

We can connect the I2S signals to A2DP bluetooth Tx module or ESP32 for further audio processing or streaming.

FM tuner with OLED and IR remote control using ESP-01

CONFIGURATION:

//* I2S OUTPUT FM TUNER *//
// TUNER: RDA7088
// CPU: ESP-01S or ESP-01
// OLED: 128x32 or 128x64
// IR: NEC 38kHz 21 Keys
// OUTPUT: I2S (16bits upto 48kHz)
// I2S DAC: PCM5102A or MAX98357A or UDA1334A or PCM5100
// INPUT: 5V or 3.7V Li
// VERSION: 1.0 // 30th DEC 2022 //
// ESP-01 CONNECTIONs //
// IO0 - SDA
// IO2 - SCL
// RX - IR Rx I/P
// RST - 10kΩ-/\/\/\- 3V3
// EN - 12kΩ-/\/\/\- 3V3
// 3V3 - 3V3
// GND - GND
// TX - 4.7kΩ-/\/\/\- 3V3 [UNUSED]-AVAILABLE FOR FUTURE USE
// EEPROM AT24C02 or AT24C04

For best audio experience we need to connect the I2S DAC audio output to external self-powered speaker.

Code

/////////////REG:04//////////////////////WR//
  Wire.beginTransmission(0x11);
  Wire.write(0x04);
  Wire.write(0b10001000);
//         -[B#FEDCBA98]-  
//             ||||||||______(08)-AFCD AFC disable 0- afc work; 1- afc disabled
//             |||||||_______(09)-SOFTMUTE_EN If 1, softmute enable
//             ||||||________(10)-RDS_FIFO_CLR 1 = clear RDS FIFO //RDSR _MODE???
//             |||||_________(11)-DE De-emphasis 0 = 75 μs; 1 = 50 μs
//             ||||__________(12)-RDS_FIFO_EN 1 = RDS fifo mode enable.
//             |||___________(13)-RBDS 1 = RBDS mode enable 0 = RDS mode only
//             ||____________(14)-STCIEN 1 = IINT ENA : STCIEN = 1 will generate low pulse on GPIO2
//             |_____________(15)-RDSIEN 0 = Disable 1 = Enable Setting STCIEN = 1 will generate a low pulse on GPIO2
  Wire.write(0b01000000);     //  Wire.write(0b01000000);
//         -[B#76543210]-  
//             ||||||||_______(0)-GPIO1[1:0] 00 = High impedance 01 = Reserved
//             |||||||________(1)-GPIO1[1:0] 10 = Low 11 = High
//             ||||||_________(2)-GPIO2[1:0] 00 = High impedance 01 = Interrupt (INT)
//             |||||__________(3)-GPIO2[1:0] 10 = Low 11 = High
//             ||||___________(4)-GPIO3[1:0] 00 = High impedance 01 = Mono/Stereo indicator (ST)
//             |||____________(5)-GPIO3[1:0] 10 = Low 11 = High
//             ||_____________(6)-I2S_ENABLED 1-ENABLED : 0-DISABLED
//             |______________(7)-GPIO1_INT_EN???
  Wire.endTransmission(); // stop transmitting
/////////////REG:04//////////////////////END//

/////////////REG:06//////////////////////WR//
  Wire.beginTransmission(0x011);
  Wire.write(0x06);
  Wire.write(0b00000010);
//         -[B#FEDCBA98]-    
//             ||||||||
//             ||||||||______(08)- WS_I_EDGE 0- normal ws internally 1, inverte ws internally
//             |||||||_______(09)- DATA_SIGNED 0- unsigned 1- signed (16-bit audio data)
//             ||||||________(10)- SCLK_I_EDGE 0- normal sclk 1- inverte sclk internally
//             |||||_________(11)- SW_LR Ws relation to l/r channel 0- ws=0->r, ws=1->l: 1- ws=0->l, ws=1->r
//             ||||__________(12)- I2S_mode_select 0- master mode: 1- slave mode
//             |||___________(13)- OPEN_MODE[1:0]
//             ||____________(14)- OPEN_MODE[1:0]
//             |_____________(15)- RSVD
  Wire.write(0b10000000);
//         -[B#76543210]-    
//             ||||||||
//             ||||||||______(0)-R_DELY-R Channel data Delay 1T
//             |||||||_______(1)-L_DELY-L channel data Delay 1T
//             ||||||________(2)-SCLK_O_EDGE If 1, invert sclk output when as master.
//             |||||_________(3)-SW_O_EDGE If 1, invert ws output when as master.  
//             ||||__________(4)[4]-I2S_SW_CNT[4:0]
//             |||___________(5)[4]-I2S_SW_CNT[4:0]
//             ||____________(6)[4]-I2S_SW_CNT[4:0]
//             |_____________(7)[4]-I2S_SW_CNT[4:0]
//                           4'b1000: WS_STEP=48.000kbps;
//                           4'b0111: WS_STEP=44.100kbps;
//                           4'b0110: WS_STEP=32.000kbps;
//                           4'b0101: WS_STEP=24.000kbps;
//                           4'b0100: WS_STEP=22.050kbps;
//                           4'b0011: WS_STEP=16.000kbps;
//                           4'b0010: WS_STEP=12.000kbps;
//                           4'b0001: WS_STEP=11.025kbps;
//                           4'b0000: WS_STEP=08.000kbps;
  Wire.endTransmission();  // stop transmitting
/////////////REG:06//////////////////////END//

Credits

mit41301

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Thanks to Matthias Hertel, Arduino-IRremote, and Bill Greiman.

I2S output FM Tuner with RDS

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Conventional FM tuner with I2C interface:

CONFIGURATION:

Schematics

FM tuner with I2C interface

Code

I2S tuner REGister 0x04H setting

I2S tuner REGister 0x06H setting

I2S tuner with RDS using ESP-01

Credits

mit41301

Comments

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I2S output FM Tuner with RDS

I2S output FM Tuner with RDS

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Conventional FM tuner with I2C interface:

CONFIGURATION:

Schematics

FM tuner with I2C interface

Code

I2S tuner REGister 0x04H setting

I2S tuner REGister 0x06H setting

I2S tuner with RDS using ESP-01

Credits

mit41301

Comments

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