The operation of setting an arbitrary value to the counter is called preset or load preset value.
The preset operation includes two kinds of cases, one is that the count value is directly set when the function is executed (the CntPreset function), and the other is that the preset register of a board is set a value in advance, and the count value will be set according to the hardware event (the CntSetPresetRegister function).
Each channel owns one preset register.