AP_ESC_Telem: support Extended DShot Telemetry v2

libraries/AP_ESC_Telem/AP_ESC_Telem.cpp

@@ -464,10 +464,17 @@ void AP_ESC_Telem::update_telem_data(const uint8_t esc_index, const AP_ESC_Telem
     if (data_mask & AP_ESC_Telem_Backend::TelemetryType::USAGE) {
         telemdata.usage_s = new_data.usage_s;
     }
+    if (data_mask & AP_ESC_Telem_Backend::TelemetryType::EDT2_STATUS) {
+        telemdata.edt2_status = merge_edt2_status(telemdata.edt2_status, new_data.edt2_status);
+    }
+    if (data_mask & AP_ESC_Telem_Backend::TelemetryType::EDT2_STRESS) {
+        telemdata.edt2_stress = merge_edt2_stress(telemdata.edt2_stress, new_data.edt2_stress);
+    }
 
     telemdata.count++;
     telemdata.types |= data_mask;
     telemdata.last_update_ms = AP_HAL::millis();
+
 }
 
 // record an update to the RPM together with timestamp, this allows the notch values to be slewed
@@ -496,6 +503,55 @@ void AP_ESC_Telem::update_rpm(const uint8_t esc_index, const float new_rpm, cons
 #endif
 }
 
+// The following is based on https://github.com/bird-sanctuary/extended-dshot-telemetry.
+// For the following part we explain the bits of Extended DShot Telemetry v2 status telemetry:
+// - bits 0-3: the "stress level"
+// - bit 5: the "error" bit   (e.g. the demag event in Bluejay)
+// - bit 6: the "warning" bit (e.g. the desync event in Bluejay)
+// - bit 7: the "alert" bit   (e.g. the stall event in Bluejay)
+
+// Since logger can read out telemetry values less frequently than they are updated,
+// it makes sense to aggregate these status bits, and to collect the maximum observed stress level.
+// To reduce the logging rate of the EDT2 messages, we will log them only once something has changed.
+// To track this, we are going to (ab)use bit 15 of the field: 1 means there is something to write.
+
+// EDTv2 also features separate "stress" messages.
+// These come more frequently, and are scaled differently (the allowed range is from 0 to 255),
+// so we have to log them separately.
+
+constexpr uint16_t EDT2_TELEM_UPDATED = 0x8000U;
+constexpr uint16_t EDT2_STRESS_0F_MASK = 0xfU;
+constexpr uint16_t EDT2_STRESS_FF_MASK = 0xffU;
+constexpr uint16_t EDT2_ERROR_MASK = 0x20U;
+constexpr uint16_t EDT2_WARNING_MASK = 0x40U;
+constexpr uint16_t EDT2_ALERT_MASK = 0x80U;
+constexpr uint16_t EDT2_ALL_BITS = EDT2_ERROR_MASK | EDT2_WARNING_MASK | EDT2_ALERT_MASK;
+
+uint16_t AP_ESC_Telem::merge_edt2_status(uint16_t old_status, uint16_t new_status)
+{
+    return uint16_t(
+        EDT2_TELEM_UPDATED | // the highest bit "telemetry is updated" is always set
+        (old_status & ~EDT2_STRESS_0F_MASK) | // old status except for the stress is preserved
+        (new_status & EDT2_ALL_BITS) | // all new status bits are included
+        std::max(old_status & EDT2_STRESS_0F_MASK, new_status & EDT2_STRESS_0F_MASK) // the stress is maxed out
+    );
+}
+
+uint16_t AP_ESC_Telem::merge_edt2_stress(uint16_t old_stress, uint16_t new_stress)
+{
+    return uint16_t(
+        EDT2_TELEM_UPDATED | // the highest bit "telemetry is updated" is always set
+        std::max(old_stress & EDT2_STRESS_FF_MASK, new_stress & EDT2_STRESS_FF_MASK) // the stress is maxed out
+    );
+}
+
+#define EDT2_HAS_NEW_DATA(status) bool(status & EDT2_TELEM_UPDATED)
+#define EDT2_STRESS_FROM_STATUS(status) uint8_t(status & EDT2_STRESS_0F_MASK)
+#define EDT2_ERROR_BIT_FROM_STATUS(status) bool(edt2_status & EDT2_ERROR_MASK)
+#define EDT2_WARNING_BIT_FROM_STATUS(status) bool(edt2_status & EDT2_WARNING_MASK)
+#define EDT2_ALERT_BIT_FROM_STATUS(status) bool(edt2_status & EDT2_ALERT_MASK)
+#define EDT2_STRESS_FROM_STRESS(stress) uint8_t(stress & EDT2_STRESS_FF_MASK)
+
 void AP_ESC_Telem::update()
 {
 #if HAL_LOGGING_ENABLED
@@ -504,7 +560,7 @@ void AP_ESC_Telem::update()
 
     for (uint8_t i = 0; i < ESC_TELEM_MAX_ESCS; i++) {
         const volatile AP_ESC_Telem_Backend::RpmData &rpmdata = _rpm_data[i];
-        const volatile AP_ESC_Telem_Backend::TelemetryData &telemdata = _telem_data[i];
+        volatile AP_ESC_Telem_Backend::TelemetryData &telemdata = _telem_data[i];
         // Push received telemetry data into the logging system
         if (logger && logger->logging_enabled()) {
             if (telemdata.last_update_ms != _last_telem_log_ms[i]
@@ -541,6 +597,50 @@ void AP_ESC_Telem::update()
                 _last_telem_log_ms[i] = telemdata.last_update_ms;
                 _last_rpm_log_us[i] = rpmdata.last_update_us;
             }
+
+            // Write an EDTv2 status message, if there is any update
+            uint16_t edt2_status = telemdata.edt2_status;
+            if (EDT2_HAS_NEW_DATA(edt2_status)) {
+                // An EDT2 status message is:
+                //   id starts from 0
+                //   alert, warning, error are flags (so 0 or 1)
+                //   stress is in [0; 15]
+                const struct log_Edt2 pkt_edt2{
+                    LOG_PACKET_HEADER_INIT(uint8_t(LOG_EDT2_MSG)),
+                    time_us     : now_us64,
+                    instance    : i,
+                    alert       : EDT2_ALERT_BIT_FROM_STATUS(edt2_status),
+                    warning     : EDT2_WARNING_BIT_FROM_STATUS(edt2_status),
+                    error       : EDT2_ERROR_BIT_FROM_STATUS(edt2_status),
+                    stress      : EDT2_STRESS_FROM_STATUS(edt2_status)
+                };
+                if (AP::logger().WriteBlock_first_succeed(&pkt_edt2, sizeof(pkt_edt2))) {
+                    // Only clean the status if the write succeeded.
+                    // This is important because, if rate limiting is enabled,
+                    // the log-on-change behavior may lose a lot of entries
+                    telemdata.edt2_status = 0;
+                }
+            }
+
+            // Write an EDTv2 stress value, if there is any update
+            uint16_t edt2_stress = telemdata.edt2_stress;
+            if (EDT2_HAS_NEW_DATA(edt2_stress)) {
+                // An EDTS stress message is:
+                //   id starts from 0
+                //   stress is in [0; 255]
+                const struct log_Edts pkt_edts{
+                    LOG_PACKET_HEADER_INIT(uint8_t(LOG_EDTS_MSG)),
+                    time_us     : now_us64,
+                    instance    : i,
+                    stress      : EDT2_STRESS_FROM_STRESS(edt2_stress)
+                };
+                if (AP::logger().WriteBlock_first_succeed(&pkt_edts, sizeof(pkt_edts))) {
+                    // Only clean the stress if the write succeeded.
+                    // This is important because, if rate limiting is enabled,
+                    // the log-on-change behavior may lose a lot of entries
+                    telemdata.edt2_stress = 0;
+                }
+            }
         }
     }
 #endif  // HAL_LOGGING_ENABLED

libraries/AP_ESC_Telem/AP_ESC_Telem.h

@@ -118,6 +118,10 @@ class AP_ESC_Telem {
     static bool rpm_data_within_timeout (const volatile AP_ESC_Telem_Backend::RpmData &instance, const uint32_t now_us, const uint32_t timeout_us);
     static bool was_rpm_data_ever_reported (const volatile AP_ESC_Telem_Backend::RpmData &instance);
 
+    // helpers that aggregate data in EDTv2 messages
+    static uint16_t merge_edt2_status(uint16_t old_status, uint16_t new_status);
+    static uint16_t merge_edt2_stress(uint16_t old_stress, uint16_t new_stress);
+
     // rpm data
     volatile AP_ESC_Telem_Backend::RpmData _rpm_data[ESC_TELEM_MAX_ESCS];
     // telemetry data

libraries/AP_ESC_Telem/AP_ESC_Telem_Backend.h

@@ -19,6 +19,8 @@ class AP_ESC_Telem_Backend {
         uint32_t last_update_ms;    // last update time in milliseconds, determines whether active
         uint16_t types;             // telemetry types present
         uint16_t count;             // number of times updated
+        uint16_t edt2_status;       // status reported by Extended DShot Telemetry v2
+        uint16_t edt2_stress;       // stress reported in dedicated messages by Extended DShot Telemetry v2
 
         // return true if the data is stale
         bool stale(uint32_t now_ms=0) const volatile;
@@ -42,6 +44,8 @@ class AP_ESC_Telem_Backend {
         USAGE       = 1 << 5,
         TEMPERATURE_EXTERNAL = 1 << 6,
         MOTOR_TEMPERATURE_EXTERNAL  = 1 << 7,
+        EDT2_STATUS = 1 << 8,
+        EDT2_STRESS = 1 << 9,
     };
 
 

libraries/AP_ESC_Telem/LogStructure.h

@@ -3,7 +3,9 @@
 #include <AP_Logger/LogStructure.h>
 
 #define LOG_IDS_FROM_ESC_TELEM                  \
-    LOG_ESC_MSG
+    LOG_ESC_MSG,                                \
+    LOG_EDT2_MSG,                               \
+    LOG_EDTS_MSG
 
 // @LoggerMessage: ESC
 // @Description: Feedback received from ESCs
@@ -34,3 +36,39 @@ struct PACKED log_Esc {
 #define LOG_STRUCTURE_FROM_ESC_TELEM \
     { LOG_ESC_MSG, sizeof(log_Esc), \
       "ESC",  "QBffffcfcf", "TimeUS,Instance,RPM,RawRPM,Volt,Curr,Temp,CTot,MotTemp,Err", "s#qqvAOaO%", "F-00--BCB-" , true },
+
+// @LoggerMessage: EDT2
+// @Description: Status received from ESCs via Extended DShot telemetry v2
+// @Field: TimeUS: microseconds since system startup
+// @Field: Instance: ESC instance number
+// @Field: Alert: the "alert" status bit
+// @Field: Warning: the "warning" status bit
+// @Field: Error: the "error" status bit
+// @Field: Stress: the maximum stress level observed for this ESC, scaled to [0..15]
+struct PACKED log_Edt2 {
+    LOG_PACKET_HEADER;
+    uint64_t time_us;
+    uint8_t instance;
+    uint8_t alert;
+    uint8_t warning;
+    uint8_t error;
+    uint8_t stress;
+};
+
+// @LoggerMessage: EDTS
+// @Description: Stress values received from ESCs via Extended DShot telemetry v2
+// @Field: TimeUS: microseconds since system startup
+// @Field: Instance: ESC instance number
+// @Field: Stress: the stress value observed for this ESC, scaled to [0..255]
+struct PACKED log_Edts {
+    LOG_PACKET_HEADER;
+    uint64_t time_us;
+    uint8_t instance;
+    uint8_t stress;
+};
+
+#define LOG_STRUCTURE_FROM_EDT2_TELEM \
+    { LOG_EDT2_MSG, sizeof(log_Edt2), \
+      "EDT2",  "QBBBBB", "TimeUS,Instance,Alert,Warning,Error,MaxStress", "s#----", "F-----" , true }, \
+    { LOG_EDTS_MSG, sizeof(log_Edts), \
+      "EDTS",  "QBB", "TimeUS,Instance,Stress", "s#-", "F--", true },

libraries/AP_HAL_ChibiOS/RCOutput_bdshot.cpp

@@ -796,10 +796,28 @@ bool RCOutput::bdshot_decode_telemetry_from_erpm(uint16_t encodederpm, uint8_t c
             break;
         case 0b100:  // Debug 1
         case 0b101:  // Debug 2
-        case 0b110:  // Stress level
-        case 0b111:  // Status
             return false;
             break;
+        case 0b110: { // Stress level
+    #if HAL_WITH_ESC_TELEM
+            TelemetryData t {
+                .edt2_stress = value
+            };
+            update_telem_data(normalized_chan, t, AP_ESC_Telem_Backend::TelemetryType::EDT2_STRESS);
+    #endif
+            return false;
+            }
+            break;
+        case 0b111: { // Status
+    #if HAL_WITH_ESC_TELEM
+            TelemetryData t {
+                .edt2_status = value
+            };
+            update_telem_data(normalized_chan, t, AP_ESC_Telem_Backend::TelemetryType::EDT2_STATUS);
+    #endif
+            return false;
+            }
+            break;
         default:     // eRPM
             break;
         }

libraries/AP_Logger/LogStructure.h

@@ -1276,6 +1276,7 @@ LOG_STRUCTURE_FROM_AVOIDANCE \
     { LOG_TERRAIN_MSG, sizeof(log_TERRAIN), \
       "TERR","QBLLHffHHf","TimeUS,Status,Lat,Lng,Spacing,TerrH,CHeight,Pending,Loaded,ROfs", "s-DU-mm--m", "F-GG-00--0", true }, \
 LOG_STRUCTURE_FROM_ESC_TELEM \
+LOG_STRUCTURE_FROM_EDT2_TELEM \
     { LOG_CSRV_MSG, sizeof(log_CSRV), \
       "CSRV","QBfffBfffffB","TimeUS,Id,Pos,Force,Speed,Pow,PosCmd,V,A,MotT,PCBT,Err", "s#---%dvAOO-", "F-000000000-", true }, \
     { LOG_PIDR_MSG, sizeof(log_PID), \