Transmit and Receive with Interrupts
For the final iteration of the “nasty” test harness I got the interrupts working for the transmitting and receiving of messages. It’s not quite simultaneous, the code sends a message every 10 seconds then goes back to receive continuous mode after each message has been sent.
public Rfm9XDevice(int chipSelectPin, int resetPin, int interruptPin)
{
var settings = new SpiConnectionSettings()
{
ChipSelectType = SpiChipSelectType.Gpio,
ChipSelectLine = chipSelectPin,
Mode = SpiMode.Mode0,
ClockFrequency = 500000,
DataBitLength = 8,
ChipSelectActiveState = false,
};
SpiController spiCntroller = SpiController.FromName(FEZ.SpiBus.Spi1);
rfm9XLoraModem = spiCntroller.GetDevice(settings);
// Factory reset pin configuration
GpioController gpioController = GpioController.GetDefault();
GpioPin resetGpioPin = gpioController.OpenPin(resetPin);
resetGpioPin.SetDriveMode(GpioPinDriveMode.Output);
resetGpioPin.Write(GpioPinValue.Low);
Thread.Sleep(10);
resetGpioPin.Write(GpioPinValue.High);
Thread.Sleep(10);
// Interrupt pin for RX message & TX done notification
InterruptGpioPin = gpioController.OpenPin(interruptPin);
resetGpioPin.SetDriveMode(GpioPinDriveMode.Input);
InterruptGpioPin.ValueChanged += InterruptGpioPin_ValueChanged;
}
private void InterruptGpioPin_ValueChanged(GpioPin sender, GpioPinValueChangedEventArgs e)
{
if (e.Edge != GpioPinEdge.RisingEdge)
{
return;
}
byte irqFlags = this.RegisterReadByte(0x12); // RegIrqFlags
Debug.WriteLine($"RegIrqFlags 0X{irqFlags:x2}");
if ((irqFlags & 0b01000000) == 0b01000000) // RxDone
{
Debug.WriteLine("Receive-Message");
byte currentFifoAddress = this.RegisterReadByte(0x10); // RegFifiRxCurrent
this.RegisterWriteByte(0x0d, currentFifoAddress); // RegFifoAddrPtr
byte numberOfBytes = this.RegisterReadByte(0x13); // RegRxNbBytes
// Allocate buffer for message
byte[] messageBytes = this.RegisterRead(0X0, numberOfBytes);
string messageText = UTF8Encoding.UTF8.GetString(messageBytes);
Debug.WriteLine($"Received {messageBytes.Length} byte message {messageText}");
}
if ((irqFlags & 0b00001000) == 0b00001000) // TxDone
{
this.RegisterWriteByte(0x01, 0b10000101); // RegOpMode set LoRa & RxContinuous
Debug.WriteLine("Transmit-Done");
}
this.RegisterWriteByte(0x40, 0b00000000); // RegDioMapping1 0b00000000 DI0 RxReady & TxReady
this.RegisterWriteByte(0x12, 0xff);// RegIrqFlags
}
…
public void RegisterDump()
{
Debug.WriteLine("Register dump");
for (byte registerIndex = 0; registerIndex <= 0x42; registerIndex++)
{
byte registerValue = this.RegisterReadByte(registerIndex);
Debug.WriteLine($"Register 0x{registerIndex:x2} - Value 0X{registerValue:x2}");
}
}
}
class Program
{
static void Main()
{
Rfm9XDevice rfm9XDevice = new Rfm9XDevice(FEZ.GpioPin.D10, FEZ.GpioPin.D9, FEZ.GpioPin.D2);
int sendCount = 0;
// 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
// More power PA Boost
rfm9XDevice.RegisterWriteByte(0x09, 0b10000000); // RegPaConfig
rfm9XDevice.RegisterWriteByte(0x01, 0b10000101); // RegOpMode set LoRa & RxContinuous
while (true)
{
rfm9XDevice.RegisterWriteByte(0x0E, 0x0); // RegFifoTxBaseAddress
// Set the Register Fifo address pointer
rfm9XDevice.RegisterWriteByte(0x0D, 0x0); // RegFifoAddrPtr
string messageText = $"Hello LoRa {sendCount += 1}!";
// load the message into the fifo
byte[] messageBytes = UTF8Encoding.UTF8.GetBytes(messageText);
rfm9XDevice.RegisterWrite(0x0, messageBytes); // RegFifo
// Set the length of the message in the fifo
rfm9XDevice.RegisterWriteByte(0x22, (byte)messageBytes.Length); // RegPayloadLength
rfm9XDevice.RegisterWriteByte(0x40, 0b01000000); // RegDioMapping1 0b00000000 DI0 RxReady & TxReady
rfm9XDevice.RegisterWriteByte(0x01, 0b10000011); // RegOpMode
Debug.WriteLine($"Sending {messageBytes.Length} bytes message {messageText}");
Thread.Sleep(10000);
}
}
}
The diagnostic output shows inbound and outbound messages (Arduino then Meadow diagnostics)
'GHIElectronics.TinyCLR.VisualStudio.ProjectSystem.dll' (Managed): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.TinyCLR\ReceiveTransmitInterrupt\bin\Debug\pe\..\ReceiveTransmitInterrupt.exe', Symbols loaded.
The thread '<No Name>' (0x2) has exited with code 0 (0x0).
Sending 13 bytes message Hello LoRa 1!
RegIrqFlags 0X08
Transmit-Done
RegIrqFlags 0X50
Receive-Message
Received 17 byte message HeLoRa World! 156
Sending 13 bytes message Hello LoRa 2!
RegIrqFlags 0X08
Transmit-Done
RegIrqFlags 0X50
Receive-Message
Received 17 byte message HeLoRa World! 158
Sending 13 bytes message Hello LoRa 3!
RegIrqFlags 0X08
Transmit-Done
RegIrqFlags 0X50
Receive-Message
Received 17 byte message HeLoRa World! 160
Sending 13 bytes message Hello LoRa 4!
RegIrqFlags 0X08
Transmit-Done
RegIrqFlags 0X50
Receive-Message
Received 17 byte message HeLoRa World! 162
Sending 13 bytes message Hello LoRa 5!
RegIrqFlags 0X08
Transmit-Done
RegIrqFlags 0X50
Receive-Message
Received 17 byte message HeLoRa World! 164
Sending 13 bytes message Hello LoRa 6!
RegIrqFlags 0X08
Transmit-Done
20:55:09.280 -> Sending HeLoRa World! 152
20:55:25.179 -> Message: Hello LoRa 1!
20:55:25.179 -> RSSI: -44
20:55:25.212 -> Snr: 9.50
20:55:25.212 ->
20:55:30.707 -> Sending HeLoRa World! 156
20:55:35.182 -> Message: Hello LoRa 2!
20:55:35.182 -> RSSI: -43
20:55:35.215 -> Snr: 9.50
20:55:35.215 ->
20:55:41.358 -> Sending HeLoRa World! 158
20:55:45.181 -> Message: Hello LoRa 3!
20:55:45.181 -> RSSI: -44
20:55:45.214 -> Snr: 9.50
20:55:45.214 ->
20:55:52.032 -> Sending HeLoRa World! 160
20:55:55.190 -> Message: Hello LoRa 4!
20:55:55.190 -> RSSI: -44
20:55:55.258 -> Snr: 9.50
20:55:55.258 ->
20:56:02.451 -> Sending HeLoRa World! 162
20:56:05.206 -> Message: Hello LoRa 5!
20:56:05.206 -> RSSI: -41
20:56:05.241 -> Snr: 9.00
20:56:05.241 ->
20:56:12.685 -> Sending HeLoRa World! 164
20:56:15.226 -> Message: Hello LoRa 6!
20:56:15.226 -> RSSI: -41
20:56:15.261 -> Snr: 9.25
20:56:15.261 ->
20:56:22.817 -> Sending HeLoRa World! 166
20:56:25.248 -> Message: Hello LoRa 7!
20:56:25.248 -> RSSI: -36
20:56:25.283 -> Snr: 10.00
20:56:25.283 ->
Next step is some refactoring to extract the register access code and merging with my Windows 10 IoT Core RMF9X library code base.
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