Add Spektrum satellite serial protocol

ExpressLRS · dkorkmazturk · Sep 23, 2023 · Feb 6, 2024 · 7f164c33eef13336d2c0f45977f9b8bbe319e567
commit 7f164c33eef13336d2c0f45977f9b8bbe319e567
diff --git a/src/html/index.html b/src/html/index.html
@@ -223,24 +223,28 @@ <h2>Serial Protocol</h2>
 									<option value='4'>SUMD</option>
 									<option value='5'>DJI RS Pro</option>
 									<option value='6'>HoTT Telemetry</option>
+									<option value='7'>DSMX 11MS</option>
+									<option value='8'>DSMX 22MS</option>
+									<option value='9'>DSM2 11MS</option>
+									<option value='10'>DSM2 22MS</option>
 								</select>
 								<label for='serial-protocol'>Serial Protocol</label>
 							</div>
 						</div>
-						<div id="sbus-config" style="display: none;">
-							<h2>SBUS Failsafe</h2>
-							Set the failsafe behaviour when using the SBUS protocol:<br/>
+						<div id="failsafe-config" style="display: none;">
+							<h2>Failsafe</h2>
+							Set the failsafe behaviour when using the SBUS or Spektrum remote receiver protocol:<br/>
 							<ul>
-								<li>"No Pulses" stops sending SBUS data when a connection to the transmitter is lost</li>
+								<li>"No Pulses" stops sending data when a connection to the transmitter is lost</li>
 								<li>"Last Position" continues to send the last received channel data along with the FAILSAFE bit set</li>
 							</ul>
 							<br/>
 							<div class="mui-select">
-								<select id='sbus-failsafe' name='serial-failsafe'>
+								<select id='serial-failsafe' name='serial-failsafe'>
 									<option value='0'>No Pulses</option>
 									<option value='1'>Last Position</option>
 								</select>
-								<label for="sbus-failsafe">SBUS Failsafe</label>
+								<label for="serial-failsafe">Failsafe</label>
 							</div>
 						</div>
 

diff --git a/src/html/scan.js b/src/html/scan.js
@@ -337,8 +337,8 @@ function updateConfig(data, options) {
     else if (proto === 2 || proto === 3 || proto === 5) { // SBUS (and inverted) or DJI-RS Pro
       _('rcvr-uart-baud').disabled = true;
       _('rcvr-uart-baud').value = '100000';
-      _('sbus-config').style.display = 'block';
-      _('sbus-failsafe').value = data['sbus-failsafe'];
+      _('failsafe-config').style.display = 'block';
+      _('serial-failsafe').value = data['serial-failsafe'];
     }
     else if (proto === 4) { // SUMD
       _('rcvr-uart-baud').disabled = true;
@@ -350,6 +350,12 @@ function updateConfig(data, options) {
       _('rcvr-uart-baud').value = '19200';
       _('sbus-config').style.display = 'none';
     }
+    else if (proto >= 7 && proto <= 10) { // Spektrum Remote Receiver
+      _('rcvr-uart-baud').disabled = true;
+      _('rcvr-uart-baud').value = '115200';
+      _('failsafe-config').style.display = 'block';
+      _('serial-failsafe').value = data['serial-failsafe'];
+    }
   }
   updatePwmSettings(data.pwm);
   _('serial-protocol').value = data['serial-protocol'];
@@ -634,7 +640,7 @@ if (_('config')) {
         return JSON.stringify({
           "pwm": getPwmFormData(),
           "serial-protocol": +_('serial-protocol').value,
-          "sbus-failsafe": +_('sbus-failsafe').value,
+          "serial-failsafe": +_('serial-failsafe').value,
           "modelid": +_('modelid').value,
           "force-tlm": +_('force-tlm').checked
         });

diff --git a/src/include/common.h b/src/include/common.h
@@ -197,7 +197,11 @@ enum eSerialProtocol : uint8_t
     PROTOCOL_INVERTED_SBUS,
 	PROTOCOL_SUMD,
     PROTOCOL_DJI_RS_PRO,
-    PROTOCOL_HOTT_TLM
+    PROTOCOL_HOTT_TLM,
+    PROTOCOL_SPEKTRUM_REMOTE_DSMX_11MS,
+    PROTOCOL_SPEKTRUM_REMOTE_DSMX_22MS,
+    PROTOCOL_SPEKTRUM_REMOTE_DSM2_11MS,
+    PROTOCOL_SPEKTRUM_REMOTE_DSM2_22MS,
 };
 
 enum eFailsafeMode : uint8_t

diff --git a/src/lib/CONFIG/config.cpp b/src/lib/CONFIG/config.cpp
@@ -1087,4 +1087,5 @@ void RxConfig::SetFailsafeMode(eFailsafeMode failsafeMode)
         m_modified = true;
     }
 }
+
 #endif
diff --git a/src/lib/LUA/rx_devLUA.cpp b/src/lib/LUA/rx_devLUA.cpp
@@ -18,7 +18,7 @@ static char pwmModes[] = "50Hz;60Hz;100Hz;160Hz;333Hz;400Hz;10kHzDuty;On/Off;DSh
 static struct luaItem_selection luaSerialProtocol = {
     {"Protocol", CRSF_TEXT_SELECTION},
     0, // value
-    "CRSF;Inverted CRSF;SBUS;Inverted SBUS;SUMD;DJI RS Pro;HoTT Telemetry",
+    "CRSF;Inverted CRSF;SBUS;Inverted SBUS;SUMD;DJI RS Pro;HoTT Telemetry;DSMX 11MS;DSMX 22MS;DSM2 11MS;DSM2 22MS",
     STR_EMPTYSPACE
 };
 
@@ -348,7 +348,11 @@ static void registerLuaParameters()
     }
   });
 
-  if (config.GetSerialProtocol() == PROTOCOL_SBUS || config.GetSerialProtocol() == PROTOCOL_INVERTED_SBUS || config.GetSerialProtocol() == PROTOCOL_DJI_RS_PRO)
+  if (config.GetSerialProtocol() == PROTOCOL_SBUS ||
+      config.GetSerialProtocol() == PROTOCOL_INVERTED_SBUS ||
+      config.GetSerialProtocol() == PROTOCOL_DJI_RS_PRO ||
+      (config.GetSerialProtocol() >= PROTOCOL_SPEKTRUM_REMOTE_DSMX_11MS &&
+       config.GetSerialProtocol() <= PROTOCOL_SPEKTRUM_REMOTE_DSM2_22MS))
   {
     registerLUAParameter(&luaFailsafeMode, [](struct luaPropertiesCommon* item, uint8_t arg){
       config.SetFailsafeMode((eFailsafeMode)arg);

diff --git a/src/lib/WIFI/devWIFI.cpp b/src/lib/WIFI/devWIFI.cpp
@@ -333,7 +333,7 @@ static void GetConfiguration(AsyncWebServerRequest *request)
     json["config"]["mode"] = wifiMode == WIFI_STA ? "STA" : "AP";
     #if defined(TARGET_RX)
     json["config"]["serial-protocol"] = config.GetSerialProtocol();
-    json["config"]["sbus-failsafe"] = config.GetFailsafeMode();
+    json["config"]["serial-failsafe"] = config.GetFailsafeMode();
     json["config"]["modelid"] = config.GetModelId();
     json["config"]["force-tlm"] = config.GetForceTlmOff();
     #if defined(GPIO_PIN_PWM_OUTPUTS)
@@ -468,7 +468,7 @@ static void UpdateConfiguration(AsyncWebServerRequest *request, JsonVariant &jso
   DBGLN("Setting serial protocol %u", protocol);
   config.SetSerialProtocol((eSerialProtocol)protocol);
 
-  uint8_t failsafe = json["sbus-failsafe"] | 0;
+  uint8_t failsafe = json["serial-failsafe"] | 0;
   DBGLN("Setting SBUS failsafe mode %u", failsafe);
   config.SetFailsafeMode((eFailsafeMode)failsafe);
 

diff --git a/src/python/serve_html.py b/src/python/serve_html.py
@@ -71,7 +71,7 @@
                 }
             ],
             "serial-protocol": 3,
-            "sbus-failsafe": 0,
+            "serial-failsafe": 0,
             "product_name": "Generic ESP8285 + 5xPWM 2.4Ghz RX",
             "lua_name": "ELRS+PWM 2400RX",
             "reg_domain": "ISM2G4",

diff --git a/src/src/rx-serial/SerialSatellite.cpp b/src/src/rx-serial/SerialSatellite.cpp
@@ -0,0 +1,111 @@
+#include "SerialSatellite.h"
+#include "CRSF.h"
+#include "config.h"
+#include "device.h"
+
+#if defined(TARGET_RX)
+
+static uint16_t crsfToSatellite(uint16_t crsfValue, uint8_t satelliteChannel, eSerialProtocol protocol)
+{
+    static constexpr uint16_t SATELLITE_MIN_US = 903;
+    static constexpr uint16_t SATELLITE_MAX_US = 2097;
+
+    const bool isDsm2_22ms = (protocol == PROTOCOL_SPEKTRUM_REMOTE_DSM2_22MS);
+
+    // Map the channel data.
+    const uint16_t us = constrain(CRSF_to_US(crsfValue), SATELLITE_MIN_US, SATELLITE_MAX_US);
+    const float divisor = isDsm2_22ms ? 1.166f : 0.583f;
+
+    uint16_t channelValue = roundf((us - SATELLITE_MIN_US) / divisor);
+
+    // Encode the channel information.
+    channelValue |= satelliteChannel << (isDsm2_22ms ? 10 : 11);
+
+#if (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
+    return __builtin_bswap16(channelValue);
+#else
+    return channelValue;
+#endif // __BYTE_ORDER__
+}
+
+uint32_t SerialSatellite::sendRCFrame(bool frameAvailable, bool frameMissed, uint32_t *channelData)
+{
+    const eSerialProtocol protocol = config.GetSerialProtocol();
+    const uint32_t callbackIntervalMs =
+        ((protocol == PROTOCOL_SPEKTRUM_REMOTE_DSMX_11MS) ||
+         (protocol == PROTOCOL_SPEKTRUM_REMOTE_DSM2_11MS))
+            ? 11
+            : 22;
+
+    if ((failsafe && config.GetFailsafeMode() == FAILSAFE_NO_PULSES) ||
+        (!sendPackets && connectionState != connected) ||
+        frameMissed)
+    {
+        // Fade count does not overflow.
+        if (sendPackets && (fadeCount < UINT8_MAX))
+        {
+            ++fadeCount;
+        }
+        return callbackIntervalMs;
+    }
+    sendPackets = true;
+
+    uint16_t outgoingPacket[SATELLITE_CHANNELS_PER_PACKET];
+
+    // Our bandwidth is limited, so try to send updates only for the channels
+    // with new values to reduce the channel update latency. Updates are
+    // checked in round-robin fashion to make sure that the channels do not
+    // starve.
+    for (uint8_t channelCount = 0, packetDataCount = 0;
+         (channelCount < SATELLITE_MAX_CHANNELS) && (packetDataCount < SATELLITE_CHANNELS_PER_PACKET);
+         ++channelCount)
+    {
+        // If the channel data is updated, add it to the packet. Or, if the
+        // space remaining in the packet is equal to the number of remaining
+        // channels to be checked for updates, just fill the packet with the
+        // remaining channels no matter if they have updates or not because we
+        // need to send exactly 7 channel data in every packet.
+        if ((prevChannelData[roundRobinIndex] != channelData[roundRobinIndex]) ||
+            ((SATELLITE_CHANNELS_PER_PACKET - packetDataCount) == (SATELLITE_MAX_CHANNELS - channelCount)))
+        {
+            prevChannelData[roundRobinIndex] = channelData[roundRobinIndex];
+            outgoingPacket[packetDataCount++] =
+                crsfToSatellite(channelData[roundRobinIndex],
+                                roundRobinIndex,
+                                protocol);
+        }
+
+        ++roundRobinIndex;
+        if (roundRobinIndex >= SATELLITE_MAX_CHANNELS)
+        {
+            roundRobinIndex = 0;
+        }
+    }
+
+    uint8_t protocolValue{};
+    switch (protocol)
+    {
+    case PROTOCOL_SPEKTRUM_REMOTE_DSMX_11MS:
+        protocolValue = 0xB2;
+        break;
+    case PROTOCOL_SPEKTRUM_REMOTE_DSMX_22MS:
+        protocolValue = 0xA2;
+        break;
+    case PROTOCOL_SPEKTRUM_REMOTE_DSM2_11MS:
+        protocolValue = 0x12;
+        break;
+    default:
+        protocolValue = 0x01;
+    }
+
+    // Transmit the fade count.
+    _outputPort->write(fadeCount);
+    // Transmit the protocol in use.
+    _outputPort->write(protocolValue);
+    // Transmit the channel data.
+    _outputPort->write(reinterpret_cast<uint8_t *>(outgoingPacket), sizeof(outgoingPacket));
+
+    return callbackIntervalMs;
+}
+
+#endif // defined(TARGET_RX)
diff --git a/src/src/rx-serial/SerialSatellite.h b/src/src/rx-serial/SerialSatellite.h
@@ -0,0 +1,26 @@
+#include "SerialIO.h"
+
+class SerialSatellite : public SerialIO
+{
+public:
+    SerialSatellite(Stream &out, Stream &in)
+        : SerialIO(&out, &in) {}
+
+    ~SerialSatellite() override = default;
+
+    void queueLinkStatisticsPacket() override {}
+    void queueMSPFrameTransmission(uint8_t *data) override {}
+    uint32_t sendRCFrame(bool frameAvailable, bool frameMissed, uint32_t *channelData) override;
+
+private:
+    static constexpr uint16_t SATELLITE_MAX_CHANNELS = 12;
+    static constexpr uint8_t SATELLITE_CHANNELS_PER_PACKET = 7;
+
+    void processBytes(uint8_t *bytes, uint16_t size) override{};
+
+    uint32_t prevChannelData[SATELLITE_CHANNELS_PER_PACKET] = {0};
+
+    uint8_t fadeCount{0};
+    uint8_t roundRobinIndex{0};
+    bool sendPackets{false};
+};
diff --git a/src/src/rx_main.cpp b/src/src/rx_main.cpp
@@ -23,6 +23,7 @@
 #include "rx-serial/SerialSUMD.h"
 #include "rx-serial/SerialAirPort.h"
 #include "rx-serial/SerialHoTT_TLM.h"
+#include "rx-serial/SerialSatellite.h"
 
 #include "rx-serial/devSerialIO.h"
 #include "devLED.h"
@@ -1186,6 +1187,7 @@ static void setupSerial()
 {
     bool sbusSerialOutput = false;
 	bool sumdSerialOutput = false;
+    bool spektrumSatelliteSerialOutput = false;
 
 #if defined(PLATFORM_ESP8266) || defined(PLATFORM_ESP32)
     bool hottTlmSerial = false;
@@ -1227,6 +1229,11 @@ static void setupSerial()
         serialBaud = 19200;
     }
 #endif
+    else if (config.GetSerialProtocol() >= PROTOCOL_SPEKTRUM_REMOTE_DSMX_11MS && config.GetSerialProtocol() <= PROTOCOL_SPEKTRUM_REMOTE_DSM2_22MS)
+    {
+        spektrumSatelliteSerialOutput = true;
+        serialBaud = 115200;
+    }
     bool invert = config.GetSerialProtocol() == PROTOCOL_SBUS || config.GetSerialProtocol() == PROTOCOL_INVERTED_CRSF || config.GetSerialProtocol() == PROTOCOL_DJI_RS_PRO;
 
 #ifdef PLATFORM_STM32
@@ -1327,6 +1334,10 @@ static void setupSerial()
         serialIO = new SerialHoTT_TLM(SERIAL_PROTOCOL_TX, SERIAL_PROTOCOL_RX);
     }
     #endif
+    else if (spektrumSatelliteSerialOutput)
+    {
+        serialIO = new SerialSatellite(SERIAL_PROTOCOL_TX, SERIAL_PROTOCOL_RX);
+    }
     else
     {
         serialIO = new SerialCRSF(SERIAL_PROTOCOL_TX, SERIAL_PROTOCOL_RX);
-Original file line number
+Diff line change
@@ Expand Up @@
             m_modified = true;
         }
     }
     #endif