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.