Notepad

 PLL At the beginning when I was looking at the I2C communication I have found out which parts of it talks with PLL, but then I carry on as I did not expect it I will need to understand it better and also since I have very vague idea about what PLL actually is. But now I have to find out in order to compute and load proper data for it into the memory. From the microphone schematics I got the basic idea Red line is quite clearly audio input from the AF microphone part. So its the signal that drives the modulation. Green line is HF output that goes to the HF amplifier stage, thats also quite clear Blue line looks like output from PLL that drives the VCO Yellow is line that goes back from the output to the Prescaler which I have found out is fancy word for frequency divider and then into the PLL  What I thougth PLL is: IC into which you send some f1 and you will get f2 thats locked to the f1 phase. But looking to the datasheet the working frequency of this PLL is actually quite ...

 EEPROM   So, I was able to connect to I2C on the board, see the communication and understand it, little bit. Now the question is, If I'm also able to read the EEPROM without removing it from PCB. Chip is quite small and de/soldering would be painful. Every time you desolder SMT component there is quite high risk that you might remove also the layer of copper which results in destruction of PCB, or in the best case, painful repair.  For the communication the easiest way is to use Arduino board and I2C library, since I have on hand ESP32 I will use this one with Arduino IDE which makes it simple. Thanks to internet there is already a guy who was playing with this particular EEPROM and Arduino, so it makes the effort even easier. Simple Copy-Paste with some modifications to read position 0x10 since I know what is stored there from the I2C communication.  For physical connection I used logic analyzer probes just connected them to the ESP32. Uploaded the program, t...