Becker Radio CD Drive Mechanism Reverse Engineering


I have BMW CD54 Professional Radios sitting around. For hobby project I dissembled one of it to see how it is working. I quickly realized that cd drive outputs audio to mainboard via I2S. There are 12 IO and power pins + 6 pin connector for I2S lines. Same Becker design used in different car brands as well, thats why I thought that if I can find out how is it working, it will be so easy to integrate an ESP32 for bluetooth music streaming.

I2S lines are connected to the SAA7325 however control lines and SAA7325 I2C lines are connected to the other proprietary Philips chip CM30430 that I cannot find the datasheet. So far the pinouts that I can traced are like this:


Do you have any suggestion for me to find out how the control working? Should I get an oscilloscope? I am adding CD Drive PCB and mainboard too.