feat: Support for ext. Multiplex MLink JR type module (#3352)

* introducing external MLink module telemetry as module PPM subtype

* implemented fix for sensor discovery display not showing all detected sensors (is in separate PR too)

implemented PPM subtypes in Companion

* add PPM subtype to model printer

finalize subtypes for PPM in Companion

* added logic to try to use HW UART with inverters turned off first (e.g. NV14), then, if not successfull use soft serial inverted (== uninverted data due to HW inverters on PCB)

changed start bit detection IRQ priority from 5 to the previous 0 (also in separate PR)

* extended telemetry timeout to 2s due to slow Mlink RSSI update rate

* changed the "NOTLM" sub-type texts to:

- "No Telem" for 128x64 (this is the max numbers of characters it can take)
- "No Telemetry" everything else including Companion

* Companion:

- lower case 1st charachter on PpmSubTypeStrings to ppmSubTypeStrings
- added telemetry hooks for ppmSubTypeStrings stringx

* simplified serial port initialization for MLink telemetry

* editorial change: corrected obsolete comment

companion/src/firmwares/edgetx/yaml_moduledata.cpp

@@ -86,6 +86,11 @@ static const YamlLookupTable r9mLut = {
   { MODULE_SUBTYPE_R9M_AUPLUS, "AUPLUS" },
 };
 
+static const YamlLookupTable ppmLut = {
+  { 0, "NOTLM" },
+  { 1, "MLINK" }
+};
+
 static const YamlLookupTable dsmLut = {
   { 0, "LP45" },
   { 1, "DSM2" },
@@ -240,6 +245,9 @@ Node convert<ModuleData>::encode(const ModuleData& rhs)
     case PULSES_LP45:
       node["subType"] = LookupValue(dsmLut, subtype);
       break;
+    case PULSES_PPM:
+      node["subType"] = LookupValue(ppmLut, subtype);
+      break; 
     case PULSES_MULTIMODULE: {
       int rfProtocol = rhs.multi.rfProtocol + 1;
       int subType = rhs.subType;
@@ -355,6 +363,9 @@ bool convert<ModuleData>::decode(const Node& node, ModuleData& rhs)
     case PULSES_PXX_R9M_LITE: {
       subType >> r9mLut >> rhs.subType;
     } break;
+    case PULSES_PPM: {
+      subType >> ppmLut >> rhs.subType;
+    } break;
     case PULSES_LP45: {
       int subProto = 0;
       subType >> dsmLut >> subProto;

companion/src/firmwares/moduledata.cpp

@@ -247,12 +247,19 @@ QString ModuleData::subTypeToString(int type) const
     "915MHz"
   };
 
+  static const QString ppmSubTypeStrings[PPM_NUM_SUBTYPES] = {
+    tr("No Telemetry"),
+    tr("MLink")
+  };
+
   if (type < 0)
     type = subType;
 
   switch (protocol) {
     case PULSES_MULTIMODULE:
       return Multiprotocols::subTypeToString((int)multi.rfProtocol, (unsigned)type);
+    case PULSES_PPM:
+      return CHECK_IN_ARRAY(ppmSubTypeStrings, type); 
     case PULSES_PXX_R9M:
       return CHECK_IN_ARRAY(strings, type);
     case PULSES_AFHDS3:

companion/src/firmwares/moduledata.h

@@ -191,6 +191,8 @@ enum ModuleSubtypeR9M {
   MODULE_SUBTYPE_R9M_LAST=MODULE_SUBTYPE_R9M_AUPLUS
 };
 
+#define PPM_NUM_SUBTYPES  2
+
 constexpr int PXX2_MAX_RECEIVERS_PER_MODULE = 3;
 constexpr int PXX2_LEN_RX_NAME              = 8;
 

companion/src/modeledit/setup.cpp

@@ -488,7 +488,7 @@ void ModulePanel::update()
         ui->telemetryBaudrate->setField(module.ghost.telemetryBaudrate);
         break;
       case PULSES_PPM:
-        mask |= MASK_PPM_FIELDS | MASK_SBUSPPM_FIELDS| MASK_CHANNELS_RANGE| MASK_CHANNELS_COUNT;
+        mask |= MASK_SUBTYPES | MASK_PPM_FIELDS | MASK_SBUSPPM_FIELDS| MASK_CHANNELS_RANGE| MASK_CHANNELS_COUNT;
         if (IS_9XRPRO(board)) {
           mask |= MASK_OPEN_DRAIN;
         }
@@ -626,6 +626,9 @@ void ModulePanel::update()
     case PULSES_AFHDS3:
         numEntries = 4;
         break;
+    case PULSES_PPM:
+        numEntries = PPM_NUM_SUBTYPES;
+        break;
     default:
       break;
     }

companion/src/modelprinter.cpp

@@ -205,6 +205,8 @@ QString ModelPrinter::printModule(int idx)
   else {
     str << printLabelValue(tr("Protocol"), ModuleData::protocolToString(module.protocol));
     if (module.protocol) {
+      if (module.protocol == PULSES_PPM)
+        str << printLabelValue(tr("Sub Type"), module.subTypeToString());
       str << printLabelValue(tr("Channels"), QString("%1-%2").arg(module.channelsStart + 1).arg(module.channelsStart + module.channelsCount));
       if (module.protocol == PULSES_PPM || module.protocol == PULSES_SBUS) {
         str << printLabelValue(tr("Frame length"), QString("%1ms").arg(printPPMFrameLength(module.ppm.frameLength)));

radio/src/gui/128x64/model_setup.cpp

@@ -255,7 +255,7 @@ enum MenuModelSetupItems {
 
 inline uint8_t MODULE_TYPE_ROWS(int moduleIdx)
 {
-  if (isModuleXJT(moduleIdx) || isModuleISRM(moduleIdx) || isModuleR9MNonAccess(moduleIdx) || isModuleDSM2(moduleIdx))
+  if (isModuleXJT(moduleIdx) || isModuleISRM(moduleIdx) || isModuleR9MNonAccess(moduleIdx) || isModuleDSM2(moduleIdx) || isModulePPM(moduleIdx))
     return 1;
   else
     return 0;
@@ -1055,6 +1055,12 @@ void menuModelSetup(event_t event)
           lcdDrawTextAtIndex(lcdNextPos + 3, y, STR_ISRM_RF_PROTOCOLS,
                              g_model.moduleData[INTERNAL_MODULE].subType,
                              menuHorizontalPosition == 1 ? attr : 0);
+#if defined(PPM)
+        else if (isModulePPM(moduleIdx))
+          lcdDrawTextAtIndex(lcdNextPos + 3, y, STR_PPM_PROTOCOLS,
+                             g_model.moduleData[moduleIdx].subType,
+                             menuHorizontalPosition == 1 ? attr : 0);
+#endif
         else if (isModuleDSM2(moduleIdx))
           lcdDrawTextAtIndex(lcdNextPos + 3, y, STR_DSM_PROTOCOLS,
                              g_model.moduleData[moduleIdx].subType,
@@ -1129,6 +1135,12 @@ void menuModelSetup(event_t event)
                   CHECK_INCDEC_MODELVAR(event,
                                         g_model.moduleData[moduleIdx].subType,
                                         DSM2_PROTO_LP45, DSM2_PROTO_DSMX);
+#if defined(PPM)
+                } else if (isModulePPM(moduleIdx)) {
+                  CHECK_INCDEC_MODELVAR(event,
+                                        g_model.moduleData[moduleIdx].subType,
+                                        PPM_PROTO_TLM_NONE, PPM_PROTO_TLM_MLINK);
+#endif
                 } else if (isModuleR9MNonAccess(moduleIdx)) {
                   g_model.moduleData[moduleIdx].subType =
                       checkIncDec(event, g_model.moduleData[moduleIdx].subType,

radio/src/gui/212x64/model_setup.cpp

@@ -333,7 +333,7 @@ void editTimerCountdown(int timerIdx, coord_t y, LcdFlags attr, event_t event)
 
 inline uint8_t EXTERNAL_MODULE_TYPE_ROW()
 {
-  if (isModuleXJT(EXTERNAL_MODULE) || isModuleR9MNonAccess(EXTERNAL_MODULE) || isModuleDSM2(EXTERNAL_MODULE) || isModuleAFHDS3(EXTERNAL_MODULE))
+  if (isModuleXJT(EXTERNAL_MODULE) || isModuleR9MNonAccess(EXTERNAL_MODULE) || isModuleDSM2(EXTERNAL_MODULE) || isModuleAFHDS3(EXTERNAL_MODULE) || isModulePPM(EXTERNAL_MODULE))
     return 1;
   else
     return 0;
@@ -1012,6 +1012,10 @@ void menuModelSetup(event_t event)
         lcdDrawTextAtIndex(MODEL_SETUP_2ND_COLUMN, y, STR_MODULE_PROTOCOLS, reusableBuffer.moduleSetup.newType, menuHorizontalPosition==0 ? attr : 0);
         if (isModuleXJT(EXTERNAL_MODULE))
           lcdDrawTextAtIndex(lcdNextPos + 3, y, STR_XJT_ACCST_RF_PROTOCOLS, g_model.moduleData[EXTERNAL_MODULE].subType, menuHorizontalPosition==1 ? attr : 0);
+#if defined(PPM)
+        else if (isModulePPM(EXTERNAL_MODULE))
+          lcdDrawTextAtIndex(lcdNextPos + 3, y, STR_PPM_PROTOCOLS, g_model.moduleData[EXTERNAL_MODULE].subType, menuHorizontalPosition==1 ? attr : 0);
+#endif
         else if (isModuleDSM2(EXTERNAL_MODULE))
           lcdDrawTextAtIndex(lcdNextPos + 3, y, STR_DSM_PROTOCOLS, g_model.moduleData[EXTERNAL_MODULE].subType, menuHorizontalPosition==1 ? attr : 0);
         else if (isModuleR9MNonAccess(EXTERNAL_MODULE))
@@ -1045,7 +1049,12 @@ void menuModelSetup(event_t event)
               case 1:
                 if (isModuleDSM2(EXTERNAL_MODULE)) {
                   CHECK_INCDEC_MODELVAR(event, g_model.moduleData[EXTERNAL_MODULE].subType, DSM2_PROTO_LP45, DSM2_PROTO_DSMX);
+                } 
+#if defined(PPM)
+                else if (isModulePPM(EXTERNAL_MODULE)) {
+                  CHECK_INCDEC_MODELVAR(event, g_model.moduleData[EXTERNAL_MODULE].subType, PPM_PROTO_TLM_NONE, PPM_PROTO_TLM_MLINK);
                 }
+#endif
 #if defined(MULTIMODULE)
                 else if (isModuleMultimodule(EXTERNAL_MODULE)) {
                   int multiRfProto = g_model.moduleData[EXTERNAL_MODULE].multi.rfProtocol;

radio/src/gui/colorlcd/module_setup.cpp

@@ -598,6 +598,17 @@ void ModuleSubTypeChoice::update()
     setAvailableHandler(nullptr);
     setTextHandler(nullptr);
   }
+#if defined(PPM)
+  else if (isModulePPM(moduleIdx)) {
+    setMin(PPM_PROTO_TLM_NONE);
+    setMax(PPM_PROTO_TLM_MLINK);
+    setValues(STR_PPM_PROTOCOLS);
+    setGetValueHandler(GET_DEFAULT(md->subType));
+    setSetValueHandler(SET_DEFAULT(md->subType));
+    setAvailableHandler(nullptr);
+    setTextHandler(nullptr);
+  }
+#endif
   else if (isModuleR9MNonAccess(moduleIdx)) {
     setMin(MODULE_SUBTYPE_R9M_FCC);
     setMax(MODULE_SUBTYPE_R9M_LAST);

radio/src/hal/module_driver.h

@@ -27,6 +27,7 @@ enum ChannelsProtocols {
   PROTOCOL_CHANNELS_UNINITIALIZED,
   PROTOCOL_CHANNELS_NONE,
   PROTOCOL_CHANNELS_PPM,
+  PROTOCOL_CHANNELS_PPM_MLINK,
   PROTOCOL_CHANNELS_PXX1,
   PROTOCOL_CHANNELS_DSM2_LP45,
   PROTOCOL_CHANNELS_DSM2_DSM2,

radio/src/pulses/modules_constants.h

@@ -210,7 +210,10 @@ enum MMDSM2Subtypes {
   MM_RF_DSM2_SUBTYPE_AUTO
 };
 
-
+enum ModuleSubtypePPM {
+  PPM_PROTO_TLM_NONE,
+  PPM_PROTO_TLM_MLINK
+};
 
 enum ModuleSubtypeDSM2 {
   DSM2_PROTO_LP45,

radio/src/pulses/ppm.cpp

@@ -27,6 +27,8 @@
 
 #include "opentx.h"
 
+#include "telemetry/mlink.h"
+
 // Minimum space after the last PPM pulse in us
 #define PPM_SAFE_MARGIN 3000 // 3ms
 
@@ -158,3 +160,37 @@ const etx_proto_driver_t PpmDriver = {
   .sendPulses = ppmSendPulses,
   .processData = nullptr,
 };
+
+//
+// additions for PPM with external MLink Module telemetry
+//
+
+static void* ppmMLinkInit(uint8_t module);
+
+const etx_proto_driver_t PpmDriverMLink = {
+  .protocol = PROTOCOL_CHANNELS_PPM_MLINK,
+  .init = ppmMLinkInit,
+  .deinit = ppmDeInit,
+  .sendPulses = ppmSendPulses,
+  .processData = processExternalMLinkSerialData,
+};
+
+static etx_serial_init ppmMLinkSerialParams = {
+  .baudrate = PPM_MSB_BAUDRATE,
+  .encoding = ETX_Encoding_8N1,
+  .direction = ETX_Dir_RX,
+  .polarity = ETX_Pol_Inverted,
+};
+
+static void* ppmMLinkInit(uint8_t module) {
+  etx_module_state_t *mod_st = (etx_module_state_t *)ppmInit(module);
+
+  if (!mod_st) 
+    return nullptr;
+
+  if (!modulePortInitSerial(module, ETX_MOD_PORT_UART, &ppmMLinkSerialParams)) {
+      modulePortInitSerial(module, ETX_MOD_PORT_SPORT_INV, &ppmMLinkSerialParams);
+  }
+
+  return (void*)mod_st;
+}

radio/src/pulses/ppm.h

@@ -24,3 +24,4 @@
 #include "hal/module_driver.h"
 
 extern const etx_proto_driver_t PpmDriver;
+extern const etx_proto_driver_t PpmDriverMLink;

radio/src/pulses/pulses.cpp

@@ -263,7 +263,16 @@ uint8_t getRequiredProtocol(uint8_t module)
 
   switch (getModuleType(module)) {
     case MODULE_TYPE_PPM:
-      protocol = PROTOCOL_CHANNELS_PPM;
+      switch (g_model.moduleData[module].subType) {
+        case PPM_PROTO_TLM_NONE: 
+          protocol = PROTOCOL_CHANNELS_PPM;
+          break;
+        case PPM_PROTO_TLM_MLINK:
+          protocol = PROTOCOL_CHANNELS_PPM_MLINK;
+          break;
+        default:
+          protocol = PROTOCOL_CHANNELS_PPM;
+      }
       break;
 
     case MODULE_TYPE_XJT_PXX1:
@@ -462,6 +471,9 @@ static void pulsesEnableModule(uint8_t module, uint8_t protocol)
   case PROTOCOL_CHANNELS_PPM:
       _init_module(module, &PpmDriver);
       break;
+  case PROTOCOL_CHANNELS_PPM_MLINK:
+      _init_module(module, &PpmDriverMLink);
+      break;  
 #endif
 
 #if defined(INTERNAL_MODULE_AFHDS2A) && defined(AFHDS2)

radio/src/storage/yaml/yaml_datastructs_funcs.cpp

@@ -1845,6 +1845,12 @@ static const struct YamlIdStr enum_FLYSKY_Subtypes[] = {
   { 0, NULL  }
 };
 
+static const struct YamlIdStr enum_PPM_Subtypes[] = {
+  { 0, "NOTLM" },
+  { 1, "MLINK" },
+  { 0, NULL  }
+};
+
 static const struct YamlIdStr enum_DSM2_Subtypes[] = {
   { 0, "LP45" },
   { 1, "DSM2" },
@@ -1888,6 +1894,8 @@ static void r_modSubtype(void* user, uint8_t* data, uint32_t bitoffs,
 #endif
   } else if (md->type == MODULE_TYPE_DSM2) {
     md->subType = yaml_parse_enum(enum_DSM2_Subtypes, val, val_len);
+  } else if (md->type == MODULE_TYPE_PPM) {
+    md->subType = yaml_parse_enum(enum_PPM_Subtypes, val, val_len);
   } else {
     md->subType = yaml_str2uint(val, val_len);
   }  
@@ -1925,6 +1933,8 @@ static bool w_modSubtype(void* user, uint8_t* data, uint32_t bitoffs,
 #endif
   } else if (md->type == MODULE_TYPE_DSM2) {
     str = yaml_output_enum(md->subType, enum_DSM2_Subtypes);
+  } else if (md->type == MODULE_TYPE_PPM) {
+    str = yaml_output_enum(md->subType, enum_PPM_Subtypes);
   } else {
     str = yaml_unsigned2str(val);
   }