RDS Decoder

 

This is an quite old project I made in 1996 but still interesting. It’s an simple RDS decoder based on TDA7330B RDS demodulator and AT90S2313 (obsolete part, replace with Atmel ATtiny2313) controller. The RDS data is displayed on an 2×16 character LCD. It shows program service name, RDS clock, TA flag status and scrolling 64 characters long radio text. The decoder needs an Stereo multiplex signal as input which is normally found at the input pin of an Stereo decoder IC in many radios.

Source code is available in assembler, I will make a C version some day. Decoding of the RDS data stream is based on Motorola’s “AN460 – RDS decoder using the MC68HC05″, see this document for details.


PCB with LCD

PCB with LCD connected


PCB top

PCB top


PCB bottom

PCB bottom


Showing program service name, clock, TA flag and scrolling radio text A

Showing program service name, clock, TA flag and scrolling radio text A


Showing program service name, clock, TA flag and scrolling radio text B

Showing program service name, clock, TA flag and scrolling radio text B

RDS Decoder in SMD

EN50067 RDS Standard EN50067_RDS_Standard.pdf
654.5 KB 1426 Downloads Details...
Motorola's AN460 Motorola RDS Decoder an460.pdf
195.2 KB 1012 Downloads Details...
RDS Decoder Firmware RDS_Decoder_v1.04.zip Version: 1.04
32.9 KB 1837 Downloads Details...
RDS Decoder Schematic rds_decoder_plans.pdf Version: 1.0
493.5 KB 2604 Downloads Details...
US RBDS Standard rbds1998.pdf
1.1 MB 919 Downloads Details...

  37 Responses to “RDS Decoder”

  1. Hello Michael,
    I WOULD LIKE YOUR TO INSTALL RDS DECODER INTO MY 25 YEARS OLD RADIO BUT UNZIPPING CODE FILE WILL DISPLAY ONLY CONFUSED SIMBOLS, CAN YOU HELP ME?
    REGARDS, merry Christmas

  2. What are the fuse settings for the ATtiny2313?

  3. I have a request to the RDS decoder. Could you send me on e-mail a file from the “drawing” of PCB (with AT90S2313 and TDA7330B in sockets like on the image)?
    On the Internet there are many projects of this type, but they are entirely or mostly built on the elements of SMD. Unfortunately I have neither the equipment nor the experience in soldering SMD elements.

    Thank you in advance for your reply.
    Greetings
    mp107

  4. What are the fuse settings for the AT902313?

    • There are no fuse settings possible on the AT90S2313.

      Also it’s obsolete, get a ATtiny2313.

  5. I am trying to interface this RDS decoder project with a TDA7000 FM receiver IC. I am however battling to find the position where to connect the two with each other. Your help will be greatly appreciated.

    Regards
    CJ Loubser

    • The TDA7000 is not suitable to receive RDS signals since this seems to be a mono radio. The RDS signal is multiplexed with the stereo audio signal and therefore you need a receiver which is capable of receiving and decoding of stereo audio.

      • Is all radio stations not already stereo multiplexed. The TDA7000 surely takes the stereo and converts it to mono?

        • It’s a question of demodulation capability of your receiver. The TDA7000 uses a simple demodulator, it doesn’t convert to mono, it simply demodulates only mono.
          The way a stereo audio is multiplexed and modulated to a RF carrier makes this possible.

          • Thanks for clarifying that to me. I now connected the RDS deocder to a stereo FM receiver. When starting the RDS decoder up the LCD only displays “RDS DECODER”. It does not srart decoding.

            The IC I connected the RDS decoder to is a RDA5807SP stereo FM tuner. I connected the MUX input cable to pin 4 since this is where the data sheet specified the FM input to be. I also connected a ground cable from one of the ground pins on the IC and connected it to the RDS decoder as specified by your schematics.

            Am I doing something wrong here?. Why won’t it start decoding? Your help will greatly be appreciated.

            Regards
            Coert

          • The RDA5807SP seems to be a full integrated tuner which requires almost no external components.
            Pin 4 is the RF input, from antenna?

            Problem is, due to full integration there is no access to multiplex signals after demodulation. Everything is on-chip. The decoder will not work with pure RF since it has no internal receiver.

            You need a tuner or tuner IC which provides a signal after IF demodulation but before stereo demultiplexer.

  6. Thank you for your help. If I try to connect the RDS decoder to say…A 30 year old stereo radio that has no IC’s on it just analog components. How do I then locate the MUX input?

    Regards
    Coert

    • Also I found a IC in a stereo FM radio. Its datasheet says it has a FM MIX input will this work?

      • What is the part number of that IC?

        • That IC proved to be monolithic so it won’t work. I do however have a old stereo radio with no IC’s in it at all. How do I go about finding the MUX signal in a radio like that?

          Regards
          Coert

          • S1A2297X01 is the part number of the IC I was talking about

          • For this IC the signal you are looking for should be available at pin 11.

          • Find the demodulator output after the 1st or even 2nd IF (intermediate frequency), prior to any filtering. This signal should contain the full multiplexed spectrum for stereo, including the RDS signal.

        • Thank you very much for your help! The decoder is up and running now and working like a dream. Your help is greatly appreciated.

          Kind Regards
          Coert

          • There is nothing to alter on my OSD board.

            1. add a high side resistor on input RPM2 to connect the input to the controller. 100-1000 Ohm will be fine.
            2. connect the second UART signal to input RPM2

            Done.

  7. How do I modify the code to display the time instead of the PI code

    Regards

    • There is no need to change the code.
      Time will be displayed when received correctly. See pictures.

  8. Dear Mickael,
    I try to help my son radio project for his studies and your built seems me perfect for that. Could you say me if your V1.04 firmware allows anothers displays than English one please ?
    In other hand, i can’t get your firmware on this site (zipped file error). Could you please send it directly to me ?
    With all my thanks.
    Stéphane

    • The files are fine, just do not uses the Windows included unzip functionality. Try 7zip instead.

      The firmware will support whatever language you want. There is anyway not much text included. Most is coming via RDS.

      • Dear Mickael,

        You were right, unzip version wasn’t included in my late windows. Now, i have your assembler firmware. Just a last question: did you develop it in c language or else please, and if yes, could we get this firmware ?
        Thank you very much.
        Stephane

        • Code is only available in assembler. It was written at the beginning of my programming attempts, had no idea about C these times.

  9. I would like to know how much cost to build this rds decoder
    thx

    • Don’t know. Just add component costs?
      I don’t build on request, just in case.

      • Do you know any site where I can find the cost?
        Sorry, but I don’t know the components name and I just need to know how much will cost to build this rds converter
        Thanks

  10. Hy Eddy, congratulation for your work. Can you help me please with a part list, schematic and the code you used for the ATtiny2313?? Looking forward for your reply. Thanks

  11. Hy. I interessed for this circuit. Have you any idea or circuit to stereo fm radio circuit? Example TDA7050

 Leave a Reply

(required)

(required)

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

Comments will be moderated! Spam deleted immediately!
Before you submit form:
Human test by Not Captcha