sx127x: Driver for Semtech sx127x radio modules

This first version of the driver has been tested with BB-FRM9x module

examples/lora/sx127x/receiver.go

@@ -0,0 +1,50 @@
+// Receives data with LoRa.
+package main
+
+import (
+	"fmt"
+	"machine"
+
+	"tinygo.org/x/drivers/lora/sx127x"
+)
+
+var loraConfig = sx127x.Config{
+	Frequency:       433998500,
+	SpreadingFactor: 7,
+	Bandwidth:       125000,
+	CodingRate:      6,
+	TxPower:         17,
+}
+
+var packet [255]byte
+
+func main() {
+	println("LoRa Receiver Example")
+
+	// SPI settings for Feather M0 LoRa board
+	csPin := machine.PB1
+	csPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	rstPin := machine.PB2
+	rstPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	dio0Pin := machine.PB3
+	dio0Pin.Configure(machine.PinConfig{Mode: machine.PinOutput})
+
+	machine.SPI0.Configure(machine.SPIConfig{})
+	loraRadio := sx127x.New(machine.SPI0, csPin, rstPin)
+	var err = loraRadio.SetupLora(loraConfig)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	println("Receiving LoRa packets...")
+
+	for {
+		packetSize := loraRadio.ParsePacket(0)
+		if packetSize > 0 {
+			println("Got packet, RSSI=", loraRadio.LastPacketRSSI())
+			size := loraRadio.ReadPacket(packet[:])
+			println(string(packet[:size]))
+		}
+	}
+}