Merge pull request #34 from DzikuVx/spi-improvements

Packet reading is now down in single SPI transaction

.vscode/arduino.json

@@ -1,6 +1,6 @@
 {
     "board": "bsfrance:avr:lora32u4",
     "sketch": "crossbow.ino",
-    "port": "COM17",
+    "port": "COM4",
     "output": "./build"
 }

crossbow.ino

@@ -1,10 +1,10 @@
 #define DEVICE_MODE_TX
 // #define DEVICE_MODE_RX
 
-#define FEATURE_TX_OLED
-// #define FORCE_TX_WITHOUT_INPUT
+// #define FEATURE_TX_OLED
+#define FORCE_TX_WITHOUT_INPUT
 
-// #define DEBUG_SERIAL
+#define DEBUG_SERIAL
 // #define DEBUG_PING_PONG
 // #define DEBUG_LED
 
@@ -60,6 +60,8 @@ RxDeviceState_t rxDeviceState = {};
 TxDeviceState_t txDeviceState = {};
 volatile RadioState_t radioState;
 
+uint8_t tmpBuffer[MAX_PACKET_SIZE];
+
 uint8_t getRadioRssi(void)
 {
     return 164 - constrain(LoRa.packetRssi() * -1, 0, 164);
@@ -263,10 +265,12 @@ void loop(void)
 {
 
     if (radioState.bytesToRead != NO_DATA_TO_READ) {
+        LoRa.read(tmpBuffer, radioState.bytesToRead);
 
         for (int i = 0; i < radioState.bytesToRead; i++) {
-            qspDecodeIncomingFrame(&qsp, LoRa.fastRead(), &rxDeviceState, &txDeviceState, &radioState);            
+            qspDecodeIncomingFrame(&qsp, tmpBuffer[i], &rxDeviceState, &txDeviceState, &radioState);            
         }
+        
         radioState.rssi = getRadioRssi();
         radioState.snr = getRadioSnr();
 
@@ -391,8 +395,12 @@ void loop(void)
 
     if (qsp.canTransmit && transmitPayload)
     {
+        uint8_t size;
         LoRa.beginPacket();
-        qspEncodeFrame(&qsp);
+        //Prepare packet
+        qspEncodeFrame(&qsp, tmpBuffer, &size);
+        //Sent it to radio in one SPI transaction
+        LoRa.write(tmpBuffer, size);
         LoRa.endPacket();
         //After ending packet, put device into receive mode again
         LoRa.receive();

lora.cpp

@@ -208,12 +208,17 @@ float LoRaClass::packetSnr()
   return ((int8_t)readRegister(REG_PKT_SNR_VALUE)) * 0.25;
 }
 
-size_t LoRaClass::write(uint8_t byte)
+void LoRaClass::write(uint8_t data)
 {
-  return write(&byte, sizeof(byte));
+  int currentLength = readRegister(REG_PAYLOAD_LENGTH);
+
+  writeRegister(REG_FIFO, data);
+
+  // update length
+  writeRegister(REG_PAYLOAD_LENGTH, currentLength + 1);
 }
 
-size_t LoRaClass::write(const uint8_t *buffer, size_t size)
+void LoRaClass::write(uint8_t buffer[], size_t size)
 {
   int currentLength = readRegister(REG_PAYLOAD_LENGTH);
 
@@ -222,15 +227,10 @@ size_t LoRaClass::write(const uint8_t *buffer, size_t size)
     size = MAX_PKT_LENGTH - currentLength;
   }
 
-  // write data
-  for (size_t i = 0; i < size; i++) {
-    writeRegister(REG_FIFO, buffer[i]);
-  }
+  writeRegister(REG_FIFO, buffer, size);
 
   // update length
   writeRegister(REG_PAYLOAD_LENGTH, currentLength + size);
-
-  return size;
 }
 
 int LoRaClass::available()
@@ -244,6 +244,11 @@ int LoRaClass::fastRead() {
   return readRegister(REG_FIFO);
 }
 
+void LoRaClass::read(uint8_t buffer[], uint8_t size) {
+  _packetIndex += size;
+  return readRegister(REG_FIFO, buffer, size);
+}
+
 int LoRaClass::read()
 {
   if (!available()) {
@@ -498,6 +503,29 @@ uint8_t LoRaClass::singleTransfer(uint8_t address, uint8_t value)
   return response;
 }
 
+void LoRaClass::writeRegister(uint8_t address, uint8_t buffer[], size_t size)
+{
+  bufferTransfer(address | 0x80, buffer, size);
+}
+
+void LoRaClass::readRegister(uint8_t address, uint8_t buffer[], size_t size)
+{
+  bufferTransfer(address & 0x7f, buffer, size);
+}
+
+void LoRaClass::bufferTransfer(uint8_t address, uint8_t buffer[], uint8_t size) {
+  uint8_t response;
+  
+  digitalWrite(_ss, LOW);
+
+  SPI.beginTransaction(_spiSettings);
+  SPI.transfer(address);
+  SPI.transfer(buffer, size);
+  SPI.endTransaction();
+
+  digitalWrite(_ss, HIGH); 
+}
+
 void LoRaClass::onDio0Rise()
 {
   LoRa.handleDio0Rise();

lora.h

@@ -30,11 +30,12 @@ public:
   int packetRssi();
   float packetSnr();
 
-  size_t write(uint8_t byte);
-  size_t write(const uint8_t *buffer, size_t size);
+  void write(uint8_t byte);
+  void write(uint8_t buffer[], size_t size);
   int available();
   int read();
   int fastRead();
+  void read(uint8_t buffer[], uint8_t size);
 
   void onReceive(void(*callback)(int));
 
@@ -69,6 +70,10 @@ private:
   void writeRegister(uint8_t address, uint8_t value);
   uint8_t singleTransfer(uint8_t address, uint8_t value);
 
+  void readRegister(uint8_t address, uint8_t buffer[], size_t size);
+  void writeRegister(uint8_t address, uint8_t buffer[], size_t size);
+  void bufferTransfer(uint8_t address, uint8_t buffer[], uint8_t size);
+
   static void onDio0Rise();
 
 private:

qsp.cpp

@@ -230,26 +230,27 @@ void qspDecodeIncomingFrame(
 /**
  * Encode frame is corrent format and write to hardware
  */
-void qspEncodeFrame(QspConfiguration_t *qsp) {
+void qspEncodeFrame(QspConfiguration_t *qsp, uint8_t buffer[], uint8_t *size) {
     //Zero CRC
     qsp->crc = 0;
 
-    //Write CHANNEL_ID
-    qsp->hardwareWriteFunction(CHANNEL_ID, qsp);
+    qspComputeCrc(qsp, CHANNEL_ID);
+    buffer[0] = CHANNEL_ID;
 
     //Write frame type and length
     uint8_t data = qsp->payloadLength & 0x0f;
     data |= (qsp->frameToSend << 4) & 0xf0;
-    qsp->hardwareWriteFunction(data, qsp);
+    qspComputeCrc(qsp, data);
+    buffer[1] = data;
 
-    //Write payload
     for (uint8_t i = 0; i < qsp->payloadLength; i++)
     {
-        qsp->hardwareWriteFunction(qsp->payload[i], qsp);
+        qspComputeCrc(qsp, qsp->payload[i]);
+        buffer[i + 2] = qsp->payload[i];
     }
 
-    //Finally write CRC
-    qsp->hardwareWriteFunction(qsp->crc, qsp);
+    buffer[qsp->payloadLength + 2] = qsp->crc;
+    *size = qsp->payloadLength + 3; //Total length of QSP frame
 }
 
 void encodePingPayload(QspConfiguration_t *qsp, uint32_t currentMicros) {

qsp.h

@@ -17,6 +17,6 @@ void qspDecodeIncomingFrame(
     RadioState_t *radioState
 );
 void qspClearPayload(QspConfiguration_t *qsp);
-void qspEncodeFrame(QspConfiguration_t *qsp);
+void qspEncodeFrame(QspConfiguration_t *qsp, uint8_t buffer[], uint8_t *size);
 
 void encodePingPayload(QspConfiguration_t *qsp, uint32_t currentMicros);