Transmit Interrupt
Starting with the TransmitBasic sample application I modified the code so that a hardware interrupt (specified in RegDioMapping1) was generated on TxDone (FIFO Payload Transmission completed).
The application inserts a message into the RFM95 transmit FIFO every 10 seconds with confirmation of transmission displayed shortly afterwards
public Rfm9XDevice(IIODevice device, ISpiBus spiBus, IPin chipSelectPin, IPin resetPin, IPin interruptPin)
{
// Chip select pin configuration
ChipSelectGpioPin = device.CreateDigitalOutputPort(chipSelectPin, initialState: true);
if (ChipSelectGpioPin == null)
{
Console.WriteLine("ChipSelectGpioPin == null");
}
// Factory reset pin configuration
IDigitalOutputPort resetGpioPin = device.CreateDigitalOutputPort(resetPin);
if (resetGpioPin == null)
{
Console.WriteLine("resetGpioPin == null");
}
resetGpioPin.State = false;
Task.Delay(10);
resetGpioPin.State = true;
Task.Delay(10);
// Interrupt pin for RX message & TX done notification
InterruptGpioPin = device.CreateDigitalInputPort(interruptPin, InterruptMode.EdgeRising);
InterruptGpioPin.Changed += InterruptGpioPin_ValueChanged;
Rfm9XLoraModem = new SpiPeripheral(spiBus, ChipSelectGpioPin);
if (Rfm9XLoraModem == null)
{
Console.WriteLine("Rfm9XLoraModem == null");
}
}
private void InterruptGpioPin_ValueChanged(object sender, DigitalInputPortEventArgs args)
{
byte irqFlags = this.RegisterReadByte(0x12); // RegIrqFlags
this.RegisterWriteByte(0x12, 0xff);// Clear RegIrqFlags
//Console.WriteLine(string.Format("RegIrqFlags:{0}", Convert.ToString(irqFlags, 2).PadLeft(8, '0')));
if ((irqFlags & 0b00001000) == 0b00001000) // TxDone
{
Console.WriteLine("Transmit-Done");
}
}
…
public class MeadowApp : App<F7Micro, MeadowApp>
{
private Rfm9XDevice rfm9XDevice;
public MeadowApp()
{
ISpiBus spiBus = Device.CreateSpiBus(500);
if (spiBus == null)
{
Console.WriteLine("spiBus == null");
}
rfm9XDevice = new Rfm9XDevice(Device, spiBus, Device.Pins.D09, Device.Pins.D11, Device.Pins.D10);
// 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);
// More power PA Boost
rfm9XDevice.RegisterWriteByte(0x09, 0b10000000); // RegPaConfig
// Interrupt on TxDone
rfm9XDevice.RegisterWriteByte(0x40, 0b01000000); // RegDioMapping1 0b00000000 DI0 TxDone
while (true)
{
// Set the Register Fifo address pointer
rfm9XDevice.RegisterWriteByte(0x0E, 0x00); // RegFifoTxBaseAddress
// Set the Register Fifo address pointer
rfm9XDevice.RegisterWriteByte(0x0D, 0x0); // RegFifoAddrPtr
string messageText = "Hello LoRa!";
// 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
Console.WriteLine("Sending {0} bytes message {1}", messageBytes.Length, messageText);
rfm9XDevice.RegisterWriteByte(0x01, 0b10000011); // RegOpMode
Task.Delay(10000).Wait();
}
}
}
The output in the debug window
'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll'.
'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\TransmitInterrupt\bin\Debug\net472\App.exe'. Symbols loaded.
'App.exe' (CLR v4.0.30319: App.exe): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\TransmitInterrupt\bin\Debug\net472\Meadow.dll'.
The program '[11164] App.exe: Program Trace' has exited with code 0 (0x0).
The program '[11164] App.exe' has exited with code 0 (0x0).
.
.
DirectRegisterAccess = True
.
.
Sending 11 bytes message Hello LoRa!
Transmit-Done
Sending 11 bytes message Hello LoRa!
Transmit-Done
Sending 11 bytes message Hello LoRa!
Transmit-Done
On the Arduino test client the serial monitor displayed
13:02:09.098 -> Sending HeLoRa World! 4
13:02:19.130 -> Message: ⸮LoRaIoT1Maduino2at 79.7,ah 39,wsa 6,wsg 13,wd 28.13,r 0.00,
13:02:19.177 -> RSSI: -72
13:02:19.177 -> Snr: 9.25
13:02:19.177 ->
13:02:19.431 -> Sending HeLoRa World! 6
13:02:29.994 -> Sending HeLoRa World! 8
13:02:32.000 -> Message: Hello LoRa!
13:02:32.000 -> RSSI: -46
13:02:32.047 -> Snr: 9.50
13:02:32.047 ->
13:02:40.750 -> Sending HeLoRa World! 10
13:02:42.260 -> Message: Hello LoRa!
13:02:42.260 -> RSSI: -45
13:02:42.314 -> Snr: 9.50
13:02:42.314 ->
13:02:51.286 -> Sending HeLoRa World! 12
13:02:52.541 -> Message: Hello LoRa!
13:02:52.541 -> RSSI: -45
13:02:52.541 -> Snr: 9.75
13:02:52.541 ->
13:03:02.112 -> Sending HeLoRa World! 14
13:03:02.745 -> Message: Hello LoRa!
13:03:02.745 -> RSSI: -45
13:03:02.792 -> Snr: 9.50
13:03:02.792 ->
Now that I’m confident my hardware is all working the next step will be building a full featured client based on my Windows 10 IoT Core library.
