sx126x: Driver for Semtech sx126x radio modules and optional RF Switch.

This first version of the driver has been tested with STM32WL SoC,
	which embeddeds SX1262 radio on the same die.

examples/sx126x/rfswitch/gnse.go

@@ -0,0 +1,61 @@
+//go:build gnse
+// +build gnse
+
+/*
+ Generic Node Sensor Edition
+ RFSwitch
+
+ Disable Switch   :  PB8=OFF PA0=OFF  PA1=OFF
+ Enable RX        :  PB8=ON  PA0=ON   PA1=OFF
+ Enable TX RFO LP :  PB8=ON  PA0=ON   PA1=ON
+ Enable TX RFO HP :  PB8=ON  PA0=OFF  PA1=ON
+*/
+package rfswitch
+
+import (
+	"machine"
+
+	"tinygo.org/x/drivers/sx126x"
+)
+
+type CustomSwitch struct {
+}
+
+var (
+	rfstate int
+)
+
+func (s CustomSwitch) InitRFSwitch() {
+	machine.RF_FE_CTRL1.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	machine.RF_FE_CTRL2.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	machine.RF_FE_CTRL3.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	rfstate = -1 //Unknown
+}
+
+func (s CustomSwitch) SetRfSwitchMode(mode int) error {
+	if mode == rfstate {
+		return nil
+	}
+
+	switch mode {
+
+	case sx126x.RFSWITCH_TX_HP:
+		machine.RF_FE_CTRL1.Set(false)
+		machine.RF_FE_CTRL2.Set(true)
+		machine.RF_FE_CTRL3.Set(true)
+
+	case sx126x.RFSWITCH_TX_LP:
+		machine.RF_FE_CTRL1.Set(true)
+		machine.RF_FE_CTRL2.Set(true)
+		machine.RF_FE_CTRL3.Set(true)
+
+	case sx126x.RFSWITCH_RX:
+		machine.RF_FE_CTRL1.Set(true)
+		machine.RF_FE_CTRL2.Set(false)
+		machine.RF_FE_CTRL3.Set(true)
+	}
+
+	rfstate = mode
+
+	return nil
+}