Receive Basic
For testing this code I used the same version of the LoRaSetSyncWord example as Transmit Basic
15:01:06.073 -> LoRa init succeeded.
15:01:06.584 -> Sending HeLoRa World! 0
15:01:08.489 -> Message: ⸮LoRaIoT1Maduino2at 74.3,ah 56,wsa 2,wsg 6,wd 15.75,r 0.00,
15:01:08.593 -> RSSI: -76
15:01:08.593 -> Snr: 9.25
15:01:08.593 ->
15:01:17.575 -> Sending HeLoRa World! 2
15:01:28.352 -> Sending HeLoRa World! 4
15:01:38.675 -> Sending HeLoRa World! 6
15:01:49.239 -> Sending HeLoRa World! 8
15:02:00.006 -> Sending HeLoRa World! 10
The TinyCLR-OS code builds on my TinyCLR-OS Transmit Basic samples.
class Program
{
static void Main()
{
Rfm9XDevice rfm9XDevice = new Rfm9XDevice(FEZ.GpioPin.D10, FEZ.GpioPin.D9);
// Put device into LoRa + Sleep mode
rfm9XDevice.RegisterWriteByte(0x01, 0b10000000); // RegOpMode
// Set the frequency to 915MHz
byte[] frequencyWriteBytes = { 0xE4, 0xC0, 0x00 }; // RegFrMsb, RegFrMid, RegFrLsb
rfm9XDevice.RegisterWrite(0x06, frequencyWriteBytes);
rfm9XDevice.RegisterWriteByte(0x0F, 0x0); // RegFifoRxBaseAddress
rfm9XDevice.RegisterWriteByte(0x01, 0b10000101); // RegOpMode set LoRa & RxContinuous
while (true)
{
// Wait until a packet is received, no timeouts in PoC
Debug.WriteLine("Receive-Wait");
byte irqFlags = rfm9XDevice.RegisterReadByte(0x12); // RegIrqFlags
while ((irqFlags & 0b01000000) == 0) // wait until RxDone cleared
{
Thread.Sleep(100);
irqFlags = rfm9XDevice.RegisterReadByte(0x12); // RegIrqFlags
//Debug.Write(".");
}
Debug.WriteLine("");
Debug.WriteLine($"RegIrqFlags 0X{irqFlags:X2}");
Debug.WriteLine("Receive-Message");
byte currentFifoAddress = rfm9XDevice.RegisterReadByte(0x10); // RegFifiRxCurrent
rfm9XDevice.RegisterWriteByte(0x0d, currentFifoAddress); // RegFifoAddrPtr
byte numberOfBytes = rfm9XDevice.RegisterReadByte(0x13); // RegRxNbBytes
byte[] messageBytes = rfm9XDevice.RegisterRead(0x00, numberOfBytes); // RegFifo
rfm9XDevice.RegisterWriteByte(0x0d, 0);
rfm9XDevice.RegisterWriteByte(0x12, 0b11111111); // RegIrqFlags clear all the bits
string messageText = UTF8Encoding.UTF8.GetString(messageBytes);
Debug.WriteLine($"Received {messageBytes.Length} byte message {messageText}");
Debug.WriteLine("Receive-Done");
}
}
}
The receive code works reliably but has no error detection or correction capability.
RegIrqFlags 0X50
Receive-Message
Received 15 byte message HeLoRa World! 0
Receive-Done
Receive-Wait
RegIrqFlags 0X50
Receive-Message
Received 59 byte message �LoRaIoT1Maduino2at 74.3,ah 56,wsa 2,wsg 6,wd 15.75,r 0.00,
Receive-Done
Receive-Wait
RegIrqFlags 0X50
Receive-Message
Received 15 byte message HeLoRa World! 2
Receive-Done
Receive-Wait
RegIrqFlags 0X50
Receive-Message
Received 15 byte message HeLoRa World! 4
Receive-Done
Receive-Wait
RegIrqFlags 0X50
Receive-Message
Received 15 byte message HeLoRa World! 6
Receive-Done
Receive-Wait
RegIrqFlags 0X50
Receive-Message
Received 15 byte message HeLoRa World! 8
Receive-Done
Receive-Wait
RegIrqFlags 0X50
Receive-Message
Received 16 byte message HeLoRa World! 10
Receive-Done
Receive-Wait
RegIrqFlags 0X50
Receive-Message
Received 59 byte message �LoRaIoT1Maduino2at 74.1,ah 56,wsa 3,wsg 8,wd 46.50,r 0.00,
Receive-Done
Receive-Wait
I will look at implementing some sort of carrier-sense multiple access with collision avoidance solution to reduce the number of corrupted messages when two (or possibly more devices) transmit at the same time.
