FM Tuner Evaluation Board Si4703 WRL-12938

Wireless & IoT Other Radios
1

I’m having a problem with the FM Tuner Evaluation Board Si4703 WRL-12938.

I can tune to a local FM station and correctly decode the RDS PI code, Version, PTY code and some of the text message but I don’t hear any audio.

Since I can receive and decode the RDS signal it means:

my wiring is good

the crystal and oscillator are working

I am tuned to a live station

I2C is working

I can Read and Write to the registers

I’m using 3.3 volts for power and I2C pullups.

I’ve tried 3 different headsets.

I hear one click in the headset and then silence. Reading of the RDS data continues to function

Any ideas why I hear nothing?

2

Hello whatpic,

Have you tried using your same set up with more than one of these boards?

3

Howdy whatpic!

Could be a few things:

  • - Headset impedance too low.
  • - Headset plug not fully inserted into the jack on the board.
  • - Volume turned down in software

    • For #1, Cheap earbuds or ‘walkman’ style headphones should be fine.

    For #2, Make sure the plug is in as far as it will go. A lot of times, they get stuck just before full insertion.

    For #3, Try adjusting the volume with our sample sketch and see if that helps.

    One or a combination of those should get you running.

    4

    Thanks for your suggestions.

    In System Configuration 2 Register, I have 05h[3:0] set to 1111 = 0 dBFS.

    In System Configuration 3 Register, I have 06h[8] disabled (default 0 to -28 dBFS).

    I believe these two setting should give me maximum volume.

    Also, with an oscilloscope I looked at pins 2 and 6 of the on-board TPA6111 amplifier. I see a 1.63 volt DC level with 220 mVpp pulses which appear to be synchronized with the I2C clock signal. These pulses are present only when using I2C to read the RDS data.

    On the amplifier output pins ( 1 and 7), I see the same 1.63 volt DC level with 640 mVpp pulses.

    At the LA and RA outputs, I see a 0 volt DC level with 800 mVpp pulses.

    I still hear nothing.

    Any other ideas?

    5

    Please try our library and [example sketch with a 3.3 volt Arduino board. I’ve verified that this will work with out breakout.](Si4703_FM_Tuner_Evaluation_Board/Firmware/Si4703_Example/Si4703_Example.ino at V_H1.3_L1.2.0 · sparkfun/Si4703_FM_Tuner_Evaluation_Board · GitHub)

    6

    I made a stupid mistake.

    In Power Configuration Register 02h, I had DMUTE enabled.

    The audio works now that I disabled it.

    Thanks for your help!