Is the frequency of MK and transmission the same thing?

Question

Electronics

Good night, tell me why 2 MKs (on the receiver and transmitter boards) operating at the same frequency always fall into the same cycle?
After all, the receiver always works from power, and we can turn on the transmitter at any time, and can it not happen that two devices operating with the same frequency will find themselves in a situation that when the receiver is waiting for a signal, the transmitter at its frequency will have a waiting step and vice versa circle.
Or the frequency of the MK and the frequencies that transmit the signal are different things?
Is there a good book on this topic for beginners (preferably with simple diagrams for clarity)?

Answer 1

They don't need to hit the beat.
The signal processing frequency is higher than the frequency of the transmitted signal, so the receiver does not need to be synchronized with the transmitter, it is enough to catch the beginning of the transmission, not necessarily with an accuracy of nanoseconds. (the same I2C is at 400 kHz, and your MK is at 8 MHz, it will have time to do something else during the transfer of one bit)
+ now the interfaces implemented on the periphery of the MK can work independently of the core, sometimes with their own clocking and their own buffers for receiving and transmitting data, you will only have to check or load these buffers, and the peripherals themselves will send-receive data (for example, USB which works from 48 MHz, while the MK itself is clocked from 12 MHz, hardware UART)