Riddler: "Which Bluetooth Module Is This?!"

Hello my friends,

I need your help. A freind of mine tossed his "old" OBD II (On-Board-Diagnose – Wikipedia) bluetooth adapter away to replace it by a wifi one. through the transparent blue plastic I saw the bluetooth module shining (see pictures) and that made me greedy. Sure they are not expensive but for free is even cheaper than not expensive :slight_smile:

Well but theres already the problem: No documentation so no idea about the pinout. I googled every number printed on it (chip is CSR brand): nothing. So I hope theres one out there recognizing it. The known pins are GND and 3V3 (comming from a voltage regulator). 1-3 and 11-13 were used (as you can see by the soldering marks).

I'll be greateful for every tipp!

lny

Ok found out by myself. Removed the polish and followed the traces to the MCU, a PIC18F25K80 and by its pinout it got clear.

The pinout and the footprint is compatible with HC-04 pintout/footprint (see picture).