I traced the SPI between the RF receiver (AMD A7125) and the MCU. It seems that a datachunk is 19 bytes and every 2 chunk is equal. I expected that only one byte (or bit) is changed, when I press a button (f.e. X) – but there are several bytes changed in the chunk.
I assumed the following SPI parameters: – CPOL 0 – CHPA 1 – 8 bit – MSB first
Have anyone this protocol/communication decoded? 🙂