Q:

How to use setModemRegisters in RF24

The below picture is the introduction of setModemRegisters .

First: What is the mean of ModemConfig* config? I mean: how to write the parameter. Maybe just give a example, and it will be better if it's suitable for this SO question.
Second: What is the mean of data rate? It is the speed of SPI between the SI4463 and MCU or speed of two SI4463  ?
Third, What is the mean of bandwidths? I never saw it...

Thanks for any help . 

A:

ModemConfig * config is a pointer to a ModemConfig struct.
You need to create a ModemConfig struct, populate it then pass a pointer to it in the call to the setModemConfig() function.
Something like this:
// create the struct
ModemConfig mc = ModemConfig();

... //populate the struct values

// then call the function
setModemConfig(&mc);

The datarate is the rate at which you are sending information over the radio channel (not between the MCU and the Si4463).
The bandwidth is the range of frequencies used in the radio transmission (e.g. in FSK if a low/0 is 99.95MHz and a high/1 is 100.05Mhz then the bandwidth would be 100Khz)

