Add method to acknowledge answers

emulator/iSkipper/examples/capture/capture.ino

@@ -3,13 +3,14 @@
 #include <string.h>
 
 /* UPDATE THESE FOR YOUR PARTICULAR BOARD */
-#define IS_RFM69HW false //make true if using w version
+#define IS_RFM69HW true //make true if using w version
 #define IRQ_PIN 3 // This is 3 on adafruit feather
 #define CSN 8 // This is 8 on adafruit feather
 /* END THINGS YOU MUST UPDATE */
 
 
 #define MAX_BUFFERED_PACKETS 20
+#define SEND_ACKS true
 
 iClickerEmulator clicker(CSN, IRQ_PIN, digitalPinToInterrupt(IRQ_PIN), IS_RFM69HW);
 RingBufCPP<iClickerPacket, MAX_BUFFERED_PACKETS> recvBuf;
@@ -29,23 +30,29 @@ void setup()
 void loop()
 {
   char tmp[50];
-  iClickerPacket r;
+  iClickerPacket r;  
 
   //see if there is a pending packet, check if its an answer packet
-
-  while (recvBuf.pull(&r)) {
+  while (recvBuf.pull(&r) && r.type == PACKET_ANSWER) {
     uint8_t *id = r.packet.answerPacket.id;
     char answer = iClickerEmulator::answerChar(r.packet.answerPacket.answer);
     snprintf(tmp, sizeof(tmp), "Captured: %c (%02X, %02X, %02X, %02X) \n", answer, id[0], id[1], id[2], id[3]);
     Serial.println(tmp);
   }
 
   delay(100);
-
 }
 
 
 void recvPacketHandler(iClickerPacket *recvd)
 {
+    if (SEND_ACKS && recvd->type == PACKET_ANSWER) {
+      Serial.println("Sending ACK");
+      clicker.acknowledgeAnswer(&recvd->packet.answerPacket, true);
+      // restore the frequency back to AA and go back to promiscous mode
+      clicker.setChannel(iClickerChannels::AA);
+      clicker.startPromiscuous(CHANNEL_SEND, recvPacketHandler);
+    }
+
     recvBuf.add(*recvd);
 }

emulator/iSkipper/iClickerEmulator.cpp

@@ -197,6 +197,33 @@ bool iClickerEmulator::submitAnswer(uint8_t id[ICLICKER_ID_LEN], iClickerAnswer
     return true;
 }
 
+void iClickerEmulator::acknowledgeAnswer(iClickerAnswerPacket* packet, bool accept) {
+    // ACKs are either 4 (accept) or 5 (reject) bytes
+    uint8_t ack_payload[5];
+    encodeId(packet->id, ack_payload);
+
+    configureRadio(CHANNEL_RECV, ACK_SEND_SYNC_ADDR);
+
+    if (accept) {
+        // When accepting, we simply replay the encoded payload
+        // ack[0-2] = encodedId[0-2]
+        // ack[3] = (encodedId[3] & 0xF0) | answer_nibble
+        ack_payload[3] = (ack_payload[3] & 0xF0) | (0x0F & getAnswerOffset(packet->answer));
+
+        _radio.send(ack_payload, 4, false);
+    } else {
+        // ack[0-1] = encodedId[0-1]
+        // ack[2] = ~encodedId[2]
+        ack_payload[2] = ~ack_payload[2];
+        // ack[3] = (encodedId[3] & 0xF0) | 0x6
+        ack_payload[3] = (ack_payload[3] & 0xF0) | 0x6;
+        // ack[4] = 0x66
+        ack_payload[4] = 0x66;
+
+        _radio.send(ack_payload, 5, false);
+    }
+}
+
 
 void iClickerEmulator::setChannel(iClickerChannel chan)
 {

emulator/iSkipper/iClickerEmulator.h

@@ -46,6 +46,9 @@ const uint8_t answerOffsets[NUM_ANSWER_CHOICES] = {0x1, 0x5, 0xd, 0xe, 0xa, 0x2}
 const uint8_t DEFAULT_SEND_SYNC_ADDR[SEND_SYNC_ADDR_LEN] =
     {RF_SYNC_BYTE1_VALUE_IC, RF_SYNC_BYTE2_VALUE_IC , RF_SYNC_BYTE3_VALUE_IC };
 
+#define ACK_SEND_SYNC_ADDR_LEN 3
+const uint8_t ACK_SEND_SYNC_ADDR[ACK_SEND_SYNC_ADDR_LEN] = {0x55, 0x55, 0x55};
+
 
 // 5 bytes
 struct iClickerAnswerPacket
@@ -109,6 +112,7 @@ class iClickerEmulator
     bool begin(iClickerChannel chan);
     bool submitAnswer(uint8_t id[ICLICKER_ID_LEN], iClickerAnswer ans,
             bool withAck=false, uint32_t timeout=DEFAULT_ACK_TIMEOUT, bool waitClear = true);
+    void acknowledgeAnswer(iClickerAnswerPacket* packet, bool accept=true);
 
     void startPromiscuous(iClickerChannelType chanType, void (*cb)(iClickerPacket *));
     void stopPromiscuous();

emulator/iSkipper/iClickerRadio.h

@@ -6,7 +6,8 @@
 #include "RFM69.h"
 
 // threshold for triggerins fifo transmit interrupt
-#define RF_FIFOTHRESH_TXSTART_FIFOTHRESH_IC 0x04
+// (should be the [smallest packet size - 1])
+#define RF_FIFOTHRESH_TXSTART_FIFOTHRESH_IC 0x03
 
 
 //RegSyncValue1-8 for sending is: