Returns the LoRa modem registers for a link at a carrier.
The link settings.
The carrier frequency, which rules out 250 and 500 kHz below 175 MHz.
A single reception timeout in symbols, whose top bits go in RegModemConfig2.
RegModemConfig1 to 3 and the SF6 detection settings.
If the SX127x cannot use the link at the carrier.
Returns the LoRa modem registers for a link at a carrier.