Radio FM TEA5767

Introduction

The TEA5767 is a cheap FM receiver that is controlled through the I2C bus.
The radio can be tuned to the European, US, and Japanese FM bands


Required Components

  • mbed
  • module TEA5767 (datasheet)
  • audio 3.5mm plug jack


Product Specifications

  • Input Voltage 3.3V
  • I2C (required 10k pull-up resistrors)
  • 32.768 kHz clock crystal


Pin Description

NameTEA5767 pinMBED pin
SDA1P28
SCL2P27
BUSMODE3GND
W/R4NC
VCC5VOUT
GND6GND
R-OUT7--
L-OUT8--
MPXO9NC
ANT10--

/media/uploads/edodm85/tea5767_pinout.jpg


Schematic

/media/uploads/edodm85/schematictea5767.jpg

For the antenna I have use a piece of wire.


How it works

The superheterodyne receiver works in this mode: the signal from the antenna is filtered and amplified, then the signal is mixed with a sine wave pruduced from a local oscillator (LO) that shift it to a specific intermediate frequency (IF). The IF signal is itself filtered and amplified and possibly processed in additional ways. The demodulator uses the IF signal rather than the original radio frequency to recreate a copy of the original information.

http://upload.wikimedia.org/wikipedia/commons/thumb/8/88/Superhet2.svg/497px-Superhet2.svg.png

For more info read this wiki page.

The Frequency is calculated by the following formula that return a 14bits word:

/media/uploads/edodm85/formula.jpg


I2C Registers

The writing address of this device is 0x60 and it is controlled by five bytes registers.

Write mode:

Description of 1st data byte

BitSymbolDescription
7MUTEif MUTE = 1 then L and R audio are muted
6SMSearch mode: if SM = 1 then in search mode; if SM = 0 then not in search mode
5-0PLL[13:8]setting of synthesizer programmable counter for search or preset

Description of 2nd data byte

BitSymbolDescription
7-0PLL[7:0]setting of synthesizer programmable counter for search or preset

Description of 3rd data byte

BitSymbolDescription
7SUDSearch Up/Down: if SUD = 1 then search up; if SUD = 0 then search down
6-5SSL[1:0]Search Stop Level: [0-1] = low, [1-0] = mid, [1-1] = high
4HLSIHigh/Low Side Injection: if HLSI = 1 then high side LO injection; if HLSI = 0 then low side LO injection
3MSMono to Stereo: if MS = 1 then forced mono; if MS = 0 then stereo ON
2MRMute Right: if MR = 1 then the right audio channel is muted and forced mono
1MLMute Left:if ML = 1 then the left audio channel is muted and forced mono
0SWP1-

Description of 4th data byte

BitSymbolDescription
7SWP2-
6STBYStandby: if STBY = 1 then in Standby mode; if STBY = 0 then not in Standby mode
5BLBand Limits: if BL = 1 then Japanese FM band; if BL = 0 then US/Europe FM band
4XTALClock frequency: Reg PLLREF=0 and XTAL=1 clocl freq=32.768KHz
3SMUTESoft Mute: if SMUTE = 1 then soft mute is ON
2HCCHigh Cut Control: if HCC = 1 then high cut control is ON
1SNCStereo Noise Cancelling:if SNC = 1 then stereo noise cancelling is ON
0SI-

Description of 5th data byte

BitSymbolDescription
7PLLREFsee the reg XTAL
6DTCif DTC = 1 then the de-emphasis time constant is 75µs; if DTC = 0 then the de-emphasis time constant is 50µs
5-0--


Read mode:

Description of 1st data byte

BitSymbolDescription
7RFReady Flag: if RF = 1 then a station has been found or the band limit has been reached
6BLFBand Limit Flag: if BLF = 1 then the band limit has been reached
5-0PLL[13:8]setting of synthesizer programmable counter for search or preset

Description of 2nd data byte

BitSymbolDescription
7-0PLL[7:0]setting of synthesizer programmable counter for search or preset

Description of 3rd data byte

BitSymbolDescription
7STEREOStereo indication:if STEREO = 1 then stereo reception; if STEREO = 0 then mono reception
6-0IF[6:0]IF counter result

Description of 4th data byte

BitSymbolDescription
7-4LEV[3:0]level ADC output
3-1CI[2:0]Chip Identification: these bits have to be set to logic 0
0--

Description of 5th data byte

BitSymbolDescription
7-0--


Test Code

Import programTEA5767_RadioFM_Test_Code

Test Code for TEA5767 radio module


Library

Import libraryTEA5767

Library for TEA5767 FM stereo radio module


C# Program

You can download the program here: RadioFM v1.0
Is required Microsoft .NET Framework 3.5 or above.

Some screens:

/media/uploads/edodm85/screenradio1.jpg

/media/uploads/edodm85/screenradio2.jpg


Report

Please log in to post comments.