Fix to syma nrf24l01 protocol (#565)

src/main/drivers/rx_nrf24l01.c

@@ -261,7 +261,6 @@ void NRF24L01_SetupBasic(void)
     NRF24L01_WriteReg(NRF24L01_01_EN_AA, 0x00); // No auto acknowledgment
     NRF24L01_WriteReg(NRF24L01_02_EN_RXADDR, BV(NRF24L01_02_EN_RXADDR_ERX_P0));
     NRF24L01_WriteReg(NRF24L01_03_SETUP_AW, NRF24L01_03_SETUP_AW_5BYTES); // 5-byte RX/TX address
-    NRF24L01_WriteReg(NRF24L01_08_OBSERVE_TX, 0x00); // Don't count lost or retransmitted packets
     NRF24L01_WriteReg(NRF24L01_1C_DYNPD, 0x00); // Disable dynamic payload length on all pipes
 }
 
@@ -326,6 +325,9 @@ bool NRF24L01_ReadPayloadIfAvailable(uint8_t *data, uint8_t length)
 }
 
 #ifndef UNIT_TEST
+/*
+ * Fast read of payload, for use in interrupt service routine
+ */
 bool NRF24L01_ReadPayloadIfAvailableFast(uint8_t *data, uint8_t length)
 {
     // number of bits transferred = 8 * (3 + length)
@@ -333,10 +335,13 @@ bool NRF24L01_ReadPayloadIfAvailableFast(uint8_t *data, uint8_t length)
     // at 50MHz clock rate that is approximately 3 microseconds
     bool ret = false;
     ENABLE_NRF24();
-    nrf24TransferByte(R_REGISTER | (REGISTER_MASK & NRF24L01_17_FIFO_STATUS));
+    nrf24TransferByte(R_REGISTER | (REGISTER_MASK & NRF24L01_07_STATUS));
-    const uint8_t fifoStatus = nrf24TransferByte(NOP);
+    const uint8_t status = nrf24TransferByte(NOP);
-    if ((fifoStatus & BV(NRF24L01_17_FIFO_STATUS_RX_EMPTY)) == 0) {
+    if ((status & BV(NRF24L01_07_STATUS_RX_DR)) == 0) {
         ret = true;
+        // clear RX_DR flag
+        nrf24TransferByte(W_REGISTER | (REGISTER_MASK & NRF24L01_07_STATUS));
+        nrf24TransferByte(BV(NRF24L01_07_STATUS_RX_DR));
         nrf24TransferByte(R_RX_PAYLOAD);
         for (uint8_t i = 0; i < length; i++) {
             data[i] = nrf24TransferByte(NOP);

src/main/io/serial_cli.c

@@ -707,7 +707,7 @@ const clivalue_t valueTable[] = {
 #ifdef USE_RX_NRF24
     { "nrf24rx_protocol",           VAR_UINT8  | MASTER_VALUE | MODE_LOOKUP,  &masterConfig.rxConfig.nrf24rx_protocol, .config.lookup = { TABLE_NRF24_RX }, 0 },
     { "nrf24rx_id",                 VAR_UINT32 | MASTER_VALUE,  &masterConfig.rxConfig.nrf24rx_id, .config.minmax = { 0, 0 }, 0 },
-    { "nrf24rx_rf_channel_count",   VAR_UINT8  | MASTER_VALUE | MODE_LOOKUP,  &masterConfig.rxConfig.nrf24rx_rf_channel_count, .config.minmax = { 0, 8 }, 0 },
+    { "nrf24rx_rf_channel_count",   VAR_UINT8  | MASTER_VALUE,  &masterConfig.rxConfig.nrf24rx_rf_channel_count, .config.minmax = { 0, 8 }, 0 },
 #endif
 #ifdef SPEKTRUM_BIND
     { "spektrum_sat_bind",          VAR_UINT8  | MASTER_VALUE,  &masterConfig.rxConfig.spektrum_sat_bind, .config.minmax = { SPEKTRUM_SAT_BIND_DISABLED,  SPEKTRUM_SAT_BIND_MAX}, 0 },

src/main/rx/nrf24_syma.c

@@ -23,11 +23,11 @@
 #include <string.h>
 
 #include <platform.h>
-#include "build/build_config.h"
-
 
 #ifdef USE_RX_SYMA
 
+#include "build/build_config.h"
+
 #include "drivers/rx_nrf24l01.h"
 #include "drivers/system.h"
 
@@ -54,7 +54,7 @@
  * uses address received in bind packets
  * hops between 4 channels generated from address received in bind packets
  *
- * SymaX5 Protocol
+ * SymaX5C Protocol
  * No auto acknowledgment
  * Payload size is 16, static
  * Data rate is 1Mbps
@@ -222,20 +222,6 @@ static void setSymaXHoppingChannels(uint32_t addr)
     }
 }
 
-static void symaSetBound(const uint8_t* rxTxAddr)
-{
-    protocolState = STATE_DATA;
-    // using protocol NRF24L01_SYMA_X, since NRF24L01_SYMA_X5C went straight into data mode
-    // set the hopping channels as determined by the rxTxAddr received in the bind packet
-    setSymaXHoppingChannels(rxTxAddr[0]);
-    timeOfLastHop = micros();
-    packetCount = 0;
-    // set the NRF24 to use the rxTxAddr received in the bind packet
-    NRF24L01_WriteRegisterMulti(NRF24L01_0A_RX_ADDR_P0, rxTxAddr, RX_TX_ADDR_LEN);
-    symaRfChannelIndex = 0;
-    NRF24L01_SetChannel(symaRfChannels[0]);
-}
-
 /*
  * This is called periodically by the scheduler.
  * Returns NRF24_RECEIVED_DATA if a data packet was received.
@@ -243,26 +229,35 @@ static void symaSetBound(const uint8_t* rxTxAddr)
 nrf24_received_t symaNrf24DataReceived(uint8_t *payload)
 {
     nrf24_received_t ret = NRF24_RECEIVED_NONE;
-    uint32_t timeNowUs;
+
     switch (protocolState) {
     case STATE_BIND:
         if (NRF24L01_ReadPayloadIfAvailable(payload, payloadSize)) {
             const bool bindPacket = symaCheckBindPacket(payload);
             if (bindPacket) {
                 ret = NRF24_RECEIVED_BIND;
-                symaSetBound(rxTxAddr);
+                protocolState = STATE_DATA;
+                // using protocol NRF24L01_SYMA_X, since NRF24L01_SYMA_X5C went straight into data mode
+                // set the hopping channels as determined by the rxTxAddr received in the bind packet
+                setSymaXHoppingChannels(rxTxAddr[0]);
+                // set the NRF24 to use the rxTxAddr received in the bind packet
+                NRF24L01_WriteRegisterMulti(NRF24L01_0A_RX_ADDR_P0, rxTxAddr, RX_TX_ADDR_LEN);
+                packetCount = 0;
+                symaRfChannelIndex = 0;
+                NRF24L01_SetChannel(symaRfChannels[0]);
             }
         }
         break;
     case STATE_DATA:
         // read the payload, processing of payload is deferred
         if (NRF24L01_ReadPayloadIfAvailable(payload, payloadSize)) {
+            symaHopToNextChannel();
+            timeOfLastHop = micros();
             ret = NRF24_RECEIVED_DATA;
         }
-        timeNowUs = micros();
+        if (micros() > timeOfLastHop + hopTimeout) {
-        if ((ret == NRF24_RECEIVED_DATA) || (timeNowUs > timeOfLastHop + hopTimeout)) {
             symaHopToNextChannel();
-            timeOfLastHop = timeNowUs;
+            timeOfLastHop = micros();
         }
         break;
     }

src/main/target/CJMCU/target.h

@@ -73,6 +73,7 @@
 #define USE_RX_INAV
 #define USE_RX_SYMA
 #define USE_RX_V202
+//#define NRF24_DEFAULT_PROTOCOL  NRF24RX_SYMA_X5
 //#define NRF24_DEFAULT_PROTOCOL  NRF24RX_SYMA_X5C
 //#define NRF24_DEFAULT_PROTOCOL  NRF24RX_INAV
 //#define NRF24_DEFAULT_PROTOCOL  NRF24RX_H8_3D