Slots for transmitting on RX side close #8

README.md

@@ -25,8 +25,8 @@ Development, not yet functional
 | 0010   | 0x2          | Request receiver configuration | TX -> RX |
 | 0011   | 0x3          | Receiver configuration | RX -> TX |
 | 0100   | 0x4          | Set receiver configuration | TX -> RX |
-| 0101   | 0x5          | PING frame | TX -> RX |
+| 0101   | 0x5          | PING frame, uses 9 byte payload | TX -> RX |
-| 0110   | 0x6          | PONG frame | RX -> TX |
+| 0110   | 0x6          | PONG frame, the same payload as PING | RX -> TX |
 
 ### `RC_DATA` frame format
 

crossbow.ino

@@ -1,11 +1,11 @@
 #define LORA_HARDWARE_SPI
 
-#define DEVICE_MODE_TX
+// #define DEVICE_MODE_TX
-// #define DEVICE_MODE_RX
+#define DEVICE_MODE_RX
 
 #define FEATURE_TX_OLED
 
-#define DEBUG_SERIAL
+// #define DEBUG_SERIAL
 // #define DEBUG_PING_PONG
 // #define DEBUG_LED
 // #define WAIT_FOR_SERIAL
@@ -63,7 +63,7 @@ uint8_t getRadioRssi(void)
     return map(constrain(LoRa.packetRssi() * -1, 0, 164), 0, 164, 255, 0);
 }
 
-float getRadioSnr(void)
+uint8_t getRadioSnr(void)
 {
     return (uint8_t) constrain(LoRa.packetSnr(), 0, 255);
 }
@@ -209,7 +209,7 @@ int8_t rxSendSequence[16] = {
     -1,
     -1,
     -1,
-    -1,
+    QSP_FRAME_RX_HEALTH,
     -1,
     -1,
     -1,
@@ -217,7 +217,7 @@ int8_t rxSendSequence[16] = {
     -1,
     -1,
     -1,
-    -1,
+    QSP_FRAME_RX_HEALTH,
     -1,
     -1,
     -1
@@ -236,7 +236,13 @@ void updateRxDeviceState(RxDeviceState_t *rxDeviceState) {
     rxDeviceState->snr = getRadioSnr();
 }    
 
-int8_t getFrameToTransmit() {
+int8_t getFrameToTransmit(QspConfiguration_t *qsp) {
+    
+    if (qsp->forcePongFrame) {
+        qsp->forcePongFrame = false;
+        return QSP_FRAME_PONG;
+    }
+
     int8_t retVal = rxSendSequence[currentSequenceIndex];
     
     currentSequenceIndex++;
@@ -250,7 +256,7 @@ int8_t getFrameToTransmit() {
 #endif
 
 #ifdef DEVICE_MODE_TX
-int8_t getFrameToTransmit() {
+int8_t getFrameToTransmit(QspConfiguration_t *qsp) {
     int8_t retVal = txSendSequence[currentSequenceIndex];
 
     currentSequenceIndex++;
@@ -284,7 +290,7 @@ void loop(void)
         qsp.protocolState == QSP_STATE_IDLE
     ) {
         
-        int8_t frameToSend = getFrameToTransmit();
+        int8_t frameToSend = getFrameToTransmit(&qsp);
 
         if (frameToSend == QSP_FRAME_RC_DATA && !ppmReader.isReceiving()) {
             frameToSend = -1;
@@ -313,17 +319,70 @@ void loop(void)
 
 #endif
 
-    // if (
+#ifdef DEVICE_MODE_RX
-    //     qsp.forcePongFrame && 
-    //     !transmitPayload && 
-    //     qsp.protocolState == QSP_STATE_IDLE
-    // )
-    // {
-    //     qsp.forcePongFrame = false;
-    //     qsp.frameToSend = QSP_FRAME_PONG;
-    //     transmitPayload = true;
-    // }
 
+    /*
+     * This routine updates RX device state and updates one of radio channels with RSSI value
+     */
+    if (abs(currentMillis - lastRxStateTaskTime) > RX_TASK_HEALTH) {
+        lastRxStateTaskTime = currentMillis;
+        updateRxDeviceState(&rxDeviceState);
+        ppm[RSSI_CHANNEL - 1] = map(rxDeviceState.rssi, 0, 255, 1000, 2000);
+
+        if (qsp.deviceState == DEVICE_STATE_FAILSAFE) {
+            digitalWrite(LED_BUILTIN, HIGH);
+        } else {
+            digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
+        }
+    }
+
+    /*
+     * Main routine to answer to TX module
+     */
+    if (qsp.transmitWindowOpen && qsp.protocolState == QSP_STATE_IDLE) {
+
+        qsp.transmitWindowOpen = false;
+
+        int8_t frameToSend = getFrameToTransmit(&qsp);
+
+        if (frameToSend > -1) {
+            
+            qsp.frameToSend = frameToSend;
+
+            if (frameToSend != QSP_FRAME_PONG) {
+                qspClearPayload(&qsp);
+            }
+
+            switch (qsp.frameToSend) {
+                case QSP_FRAME_PONG:
+                    /*
+                     * Pong frame just responses with received payload
+                     */
+                    break;
+
+                case QSP_FRAME_RX_HEALTH:
+                    encodeRxHealthPayload(&qsp, &rxDeviceState);
+                    break;
+            }
+
+            transmitPayload = true;
+        }
+
+    }
+
+    if (currentMillis > sbusTime) {
+        sbusPreparePacket(sbusPacket, ppm, false, (qsp.deviceState == DEVICE_STATE_FAILSAFE));
+        Serial1.write(sbusPacket, SBUS_PACKET_LENGTH);
+        sbusTime = currentMillis + SBUS_UPDATE_RATE;
+    }
+
+    if (abs(currentMillis - qsp.lastFrameReceivedAt[QSP_FRAME_RC_DATA]) > RX_FAILSAFE_DELAY) {
+        qsp.deviceState = DEVICE_STATE_FAILSAFE;
+    } else {
+        qsp.deviceState = DEVICE_STATE_OK;
+    }
+
+#endif
 
 #ifdef DEVICE_MODE_TX
 
@@ -363,48 +422,6 @@ void loop(void)
 
 #endif
 
-// #ifdef DEVICE_MODE_RX
-
-//     if (currentMillis > sbusTime) {
-//         sbusPreparePacket(sbusPacket, ppm, false, (qsp.deviceState == DEVICE_STATE_FAILSAFE));
-//         Serial1.write(sbusPacket, SBUS_PACKET_LENGTH);
-
-//         sbusTime = currentMillis + SBUS_UPDATE_RATE;
-//     }
-
-//     /*
-//      * This routine updates RX device state and updates one of radio channels with RSSI value
-//      */
-//     if (currentMillis - lastRxStateTaskTime > RX_TASK_HEALTH) {
-//         lastRxStateTaskTime = currentMillis;
-//         updateRxDeviceState(&rxDeviceState);
-//         ppm[RSSI_CHANNEL - 1] = map(rxDeviceState.rssi, 0, 255, 1000, 2000);
-
-//         if (qsp.deviceState == DEVICE_STATE_FAILSAFE) {
-//             digitalWrite(LED_BUILTIN, HIGH);
-//         } else {
-//             digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
-//         }
-
-//     }
-
-//     /*
-//      * RX_HEALTH QSP frame
-//      */
-//     if (
-//         currentMillis - qsp.lastFrameTransmitedAt[QSP_FRAME_RX_HEALTH] > RX_RX_HEALTH_FRAME_RATE && 
-//         !transmitPayload && 
-//         qsp.protocolState == QSP_STATE_IDLE
-//     )
-//     {
-//         qspClearPayload(&qsp);
-//         encodeRxHealthPayload(&qsp, &rxDeviceState);
-//         qsp.frameToSend = QSP_FRAME_RX_HEALTH;
-
-//         transmitPayload = true;
-//     }
-// #endif
-
     if (qsp.canTransmit && transmitPayload)
     {
         radioPacketStart();
@@ -413,16 +430,6 @@ void loop(void)
         transmitPayload = false;
     }
 
-    /*
-     * Here we do state handling and similar operations 
-     */
-#ifdef DEVICE_MODE_RX
-    if (abs(currentMillis - qsp.lastFrameReceivedAt[QSP_FRAME_RC_DATA]) > RX_FAILSAFE_DELAY) {
-        qsp.deviceState = DEVICE_STATE_FAILSAFE;
-    } else {
-        qsp.deviceState = DEVICE_STATE_OK;
-    }
-#endif
 }
 
 #ifdef LORA_HARDWARE_SPI

qsp.cpp

@@ -204,19 +204,6 @@ void qspDecodeIncomingFrame(QspConfiguration_t *qsp, uint8_t incomingByte, int p
                 qsp->lastFrameReceivedAt[frameId] = millis();
             }
 
-            if (qsp->debugConfig & DEBUG_FLAG_SERIAL) {
-                Serial.print("Frame ");
-                Serial.print(frameId);
-                Serial.println(" received");
-            }
-
-            if (qsp->debugConfig & DEBUG_FLAG_LED) {
-                digitalWrite(LED_BUILTIN, HIGH);
-                delay(10);
-                digitalWrite(LED_BUILTIN, LOW);
-                delay(100);
-            }
-            
             switch (frameId) {
                 case QSP_FRAME_RC_DATA:
                     qspDecodeRcDataFrame(qsp, ppm);
@@ -224,12 +211,6 @@ void qspDecodeIncomingFrame(QspConfiguration_t *qsp, uint8_t incomingByte, int p
 
                 case QSP_FRAME_RX_HEALTH:
                     decodeRxHealthPayload(qsp, rxDeviceState);
-                    if (qsp->debugConfig & DEBUG_FLAG_SERIAL) {
-                        Serial.print("RX RSSI: ");
-                        Serial.println(rxDeviceState->rssi);
-                        Serial.print("RX SNR: ");
-                        Serial.println(rxDeviceState->snr);
-                    }
                     break;
 
                 case QSP_FRAME_PING:
@@ -251,6 +232,8 @@ void qspDecodeIncomingFrame(QspConfiguration_t *qsp, uint8_t incomingByte, int p
                     //TODO do something in this case
                     break;
             }
+
+            qsp->transmitWindowOpen = true;
         }
         else
         {

variables.h

@@ -11,12 +11,9 @@
 #define RX_TASK_HEALTH 200 //5Hz should be enough
 #define RSSI_CHANNEL 11
 
-#define RX_RX_HEALTH_FRAME_RATE 503
 #define TX_TRANSMIT_SLOT_RATE 57 //ms
 #define RX_FAILSAFE_DELAY (TX_TRANSMIT_SLOT_RATE * 8)
 
-#define TX_PING_RATE 2007
-
 #define CHANNEL_ID 0x01
 #define QSP_PREAMBLE 0x51
 #define QSP_PAYLOAD_LENGTH 32
@@ -82,6 +79,7 @@ struct QspConfiguration_t {
     uint8_t debugConfig = 0;
     uint32_t frameDecodingStartedAt = 0;
     uint32_t lastTxSlotTimestamp = 0;
+    bool transmitWindowOpen = false;
 };
 
 struct RxDeviceState_t {