fix: Quick fix to let CRSF be used with MPM wireless trainer - limiations apply (#1724)

* Let's do some dirty hack with MPM RX

Resolves #1671

* Use the right function to sync and shutdown sync on external MPM as well

radio/src/pulses/multi.cpp

@@ -76,6 +76,20 @@ static void sendMulti(uint8_t moduleIdx, uint8_t b)
     sendByteSbus(b);
 }
 
+static void updateMultiSync(uint8_t module)
+{
+  const auto& status = getMultiModuleStatus(module);
+  if (status.isValid() && status.isRXProto) {
+    mixerSchedulerSetPeriod(module, 0);
+  } else {
+    auto& sync = getModuleSyncStatus(module);
+    if (sync.isValid())
+      mixerSchedulerSetPeriod(module, sync.getAdjustedRefreshRate());
+    else
+      mixerSchedulerSetPeriod(module, MULTIMODULE_PERIOD);
+  }
+}
+
 static void sendFailsafeChannels(uint8_t moduleIdx)
 {
   uint32_t bits = 0;
@@ -118,6 +132,8 @@ void setupPulsesMulti(uint8_t moduleIdx)
   };
   uint8_t type=MULTI_NORMAL;
 
+  updateMultiSync(moduleIdx);
+
   // not scanning protos &&  not spectrum analyser
   if (getModuleMode(moduleIdx) == MODULE_MODE_NORMAL) {
     // Failsafe packets
@@ -202,12 +218,6 @@ void setupPulsesMultiExternalModule()
 }
 
 #if defined(INTERNAL_MODULE_MULTI)
-void setupPulsesMultiInternalModule()
-{
-  intmodulePulsesData.multi.initFrame();
-  setupPulsesMulti(INTERNAL_MODULE);
-}
-
 static void* multiInit(uint8_t module)
 {
   (void)module;

radio/src/pulses/pulses.cpp

@@ -649,15 +649,8 @@ bool setupPulsesExternalModule(uint8_t protocol)
 
 #if defined(MULTIMODULE)
     case PROTOCOL_CHANNELS_MULTIMODULE:
-    {
-      ModuleSyncStatus& status = getModuleSyncStatus(EXTERNAL_MODULE);
-      if (status.isValid())
-        mixerSchedulerSetPeriod(EXTERNAL_MODULE, status.getAdjustedRefreshRate());
-      else
-        mixerSchedulerSetPeriod(EXTERNAL_MODULE, MULTIMODULE_PERIOD);
       setupPulsesMultiExternalModule();
       return true;
-    }
 #endif
 
 #if defined(PPM)

radio/src/pulses/pulses.h

@@ -239,7 +239,6 @@ void setupPulsesLemonDSMP();
 void setupPulsesCrossfire(uint8_t idx);
 void setupPulsesGhost();
 void setupPulsesMultiExternalModule();
-void setupPulsesMultiInternalModule();
 void setupPulsesSbus();
 void setupPulsesPPMInternalModule();
 void setupPulsesPPMExternalModule();

radio/src/telemetry/multi.cpp

@@ -244,6 +244,16 @@ static void processMultiStatusPacket(const uint8_t * data, uint8_t module, uint8
   if (wasBinding && !status.isBinding() && getMultiBindStatus(module) == MULTI_BIND_INITIATED)
     setMultiBindStatus(module, MULTI_BIND_FINISHED);
 
+  // Dirty RX protocol detection
+  size_t proto_len = strnlen(status.protocolName, 8);
+  if (proto_len >= 2 &&
+      status.protocolName[proto_len - 2] == 'R' &&
+      status.protocolName[proto_len - 1] == 'X') {
+    status.isRXProto = true;
+  } else {
+    status.isRXProto = false;
+  }
+
   // update timestamp last to avoid race conditions
   status.lastUpdate = get_tmr10ms();
 }

radio/src/telemetry/multi.h

@@ -108,6 +108,7 @@ struct MultiModuleStatus {
   uint8_t flags;
   uint8_t requiresFailsafeCheck;
   uint8_t failsafeChecked;
+  uint8_t isRXProto;
   tmr10ms_t lastUpdate;
 
   uint8_t protocolPrev = 0;

radio/src/telemetry/telemetry.h

@@ -318,7 +318,7 @@ struct ModuleSyncStatus
   tmr10ms_t lastUpdate;  // in 10ms
   int16_t   currentLag;  // in us
   
-  inline bool isValid() {
+  inline bool isValid() const {
     // 2 seconds
     return (get_tmr10ms() - lastUpdate < 200);
   }