2019-08-26

TEA5767 FM Stereo Radio Module

The TEA5767 FM Stereo Radio Module that I purchased from Amazon.com arrived without any documentation. Zero. Zilch. Nada. Not even a hint about where to look for documentation. This makes it a challenge to start writing software to control it. I searched for code examples and found several. But they were all written in other languages like 'C' and Python. After playing with some of the examples I was able to translate what I needed into Xojo code.

What makes the TEA5767 FM Stereo Radio Module a bit confusing is that it is actually two modules. There's the FM Stereo Radio Module and the TEA5767 Module. If you look closely at the FM Stereo Radio Module you'll see a smaller circuit board attached to it. That is the actual TEA5767 Module.

It appears that the FM Stereo Radio Module is just a bunch of support circuitry for the TEA5767 module. From what I can gather, it includes a small amplifier designed to drive a typical pair of ear-bud headphones. And it provides a convenient way to attach headphones via a 1/8" stereo audio jack.

Unlike the FM Stereo Radio Module, the TEA5767 module is well documented. The "TEA5767 Application Note" document contains everything you could possibly want to know and it's chock full of technical jargon and programming info.

Download older (2002) TEA5767 Application Note (1.1 MB .pdf file)
Download newer (2007) TEA5767 Application Note (200.4 KB .pdf file)

The antenna connection is an oddity. They used a 1/8" TRS (tip, ring, sleeve) audio jack as the connector for the supplied telescoping mast antenna. Since The Comvette Project makes use of the car's existing electric antenna, the supplied telescoping mast antenna is a throw-away item. But I needed to figure out how to connect the car antenna to the FM Stereo Radio Module. Since there's no documentation, I used an ohm-meter to find out how the supplied antenna mast was connected to its plug. It turns out that the sleeve is connected to the antenna mast and the tip and ring are unused.

So installed a 1/8" TRS plug on the end of the car's coax cable and soldered the coax antenna cable's center conductor to the sleeve of the 1/8" TRS plug.

To make the FM Stereo Radio Module easier to mount on a proto-breadboard I removed the original 90° 4-pin header and replaced it with a straight 4-pin header.

You gotta love the way the Chinese manufacturer mangled the pin labeling. SLC should be SCL (Serial Clock). The funny thing is that every one of the various clones of this board copy the same mistake.