Add bidirectional DShot ESC telemetry

docs/Settings.md

@@ -925,6 +925,26 @@ Sets the DShot beeper tone
 
 ---
 
+### dshot_bidir_enabled
+
+Enable bidirectional DShot telemetry on motor outputs. Required for RPM filtering without a separate ESC telemetry UART
+
+| Default | Min | Max |
+| --- | --- | --- |
+| OFF | OFF | ON |
+
+---
+
+### dshot_edt_enabled
+
+Enable extended DShot telemetry decoding (temperature, voltage, current in addition to eRPM)
+
+| Default | Min | Max |
+| --- | --- | --- |
+| OFF | OFF | ON |
+
+---
+
 ### dterm_lpf2_hz
 
 Dterm pre-differentiation LPF cutoff (Hz). Filters gyro before differentiation to reduce noise amplification. Higher = less delay, more noise. 0 = disabled. Values around 200-250Hz can add smoothing with small delay.

src/main/CMakeLists.txt

@@ -241,6 +241,8 @@ main_sources(COMMON_SRC
     drivers/pwm_esc_detect.h
     drivers/pwm_mapping.c
     drivers/pwm_mapping.h
+    drivers/dshot.c
+    drivers/dshot.h
     drivers/pwm_output.c
     drivers/pwm_output.h
     drivers/pinio.c

src/main/blackbox/blackbox.c

@@ -1436,8 +1436,10 @@ static void loadSlowState(blackboxSlowState_t *slow)
 
 #ifdef USE_ESC_SENSOR
     escSensorData_t * escSensor = escSensorGetData();
-    slow->escRPM = escSensor->rpm;
-    slow->escTemperature = escSensor->temperature;
+    if (escSensor) {
+        slow->escRPM = escSensor->rpm;
+        slow->escTemperature = escSensor->temperature;
+    }
 #endif
 }
 
@@ -1455,7 +1457,7 @@ static bool writeSlowFrameIfNeeded(bool allowPeriodicWrite)
     if (shouldWrite) {
         loadSlowState(&slowHistory);
     } else {
-        blackboxSlowState_t newSlowState;
+        blackboxSlowState_t newSlowState = {0};
 
         loadSlowState(&newSlowState);
 

src/main/drivers/dshot.c

@@ -0,0 +1,237 @@
+/*
+ * This file is part of Betaflight.
+ *
+ * Betaflight is free software. You can redistribute this software
+ * and/or modify this software under the terms of the GNU General
+ * Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * Betaflight is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software.
+ *
+ * If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <float.h>
+#include <string.h>
+
+#include "platform.h"
+#include "common/utils.h"
+#include "drivers/dshot.h"
+
+#ifdef USE_DSHOT
+
+#include "common/filter.h"
+#include "common/maths.h"
+
+#include "flight/mixer.h"
+#include "drivers/pwm_mapping.h"
+
+#define DSHOT_RPM_LPF_HZ 150
+
+bool useDshotTelemetry = false;
+dshotTelemetryState_t dshotTelemetryState;
+
+static pt1Filter_t motorFreqLpf[MAX_SUPPORTED_MOTORS];
+static float motorFrequencyHz[MAX_SUPPORTED_MOTORS];
+static float dshotRpm[MAX_SUPPORTED_MOTORS];
+static float dshotRpmAverage;
+static float erpmToHz;
+static bool edtAlwaysDecode;
+
+static const dshotTelemetryType_e extendedTelemetryLookup[8] = {
+    DSHOT_TELEMETRY_TYPE_ERPM,
+    DSHOT_TELEMETRY_TYPE_TEMPERATURE,
+    DSHOT_TELEMETRY_TYPE_VOLTAGE,
+    DSHOT_TELEMETRY_TYPE_CURRENT,
+    DSHOT_TELEMETRY_TYPE_DEBUG1,
+    DSHOT_TELEMETRY_TYPE_DEBUG2,
+    DSHOT_TELEMETRY_TYPE_DEBUG3,
+    DSHOT_TELEMETRY_TYPE_STATE_EVENTS,
+};
+
+static float erpmToRpm(uint32_t erpm)
+{
+    return erpm * erpmToHz * 60.0f;
+}
+
+static uint32_t dshotDecodeErpmTelemetryValue(uint16_t value)
+{
+    if (value == 0x0fff) {
+        return 0;
+    }
+
+    value = (value & 0x01ff) << ((value & 0xfe00) >> 9);
+    if (!value) {
+        return DSHOT_TELEMETRY_INVALID;
+    }
+
+    return (1000000 * 60 / 100 + value / 2) / value;
+}
+
+static void dshotDecodeTelemetryValue(uint8_t motorIndex, uint32_t *decoded, dshotTelemetryType_e *type)
+{
+    const uint16_t value = dshotTelemetryState.motorState[motorIndex].rawValue;
+    const bool edtEnabled = edtAlwaysDecode || (dshotTelemetryState.motorState[motorIndex].telemetryTypes & DSHOT_EXTENDED_TELEMETRY_MASK) != 0;
+    const unsigned telemetryType = (value & 0x0f00) >> 8;
+    const bool isErpm = !edtEnabled || (telemetryType & 0x01) || (telemetryType == 0);
+
+    if (isErpm) {
+        *decoded = dshotDecodeErpmTelemetryValue(value);
+        *type = DSHOT_TELEMETRY_TYPE_ERPM;
+    } else {
+        const unsigned typeIndex = telemetryType >> 1;
+        *type = typeIndex < ARRAYLEN(extendedTelemetryLookup) ? extendedTelemetryLookup[typeIndex] : DSHOT_TELEMETRY_TYPE_STATE_EVENTS;
+        *decoded = value & 0x00ff;
+    }
+}
+
+void dshotResetTelemetry(void)
+{
+    memset(&dshotTelemetryState, 0, sizeof(dshotTelemetryState));
+    memset(dshotRpm, 0, sizeof(dshotRpm));
+    memset(motorFrequencyHz, 0, sizeof(motorFrequencyHz));
+    dshotRpmAverage = 0.0f;
+}
+
+bool isDshotTelemetryConfigured(void)
+{
+    return useDshotTelemetry;
+}
+
+bool isDshotTelemetryActive(void)
+{
+    return useDshotTelemetry;
+}
+
+void initDshotTelemetry(timeUs_t looptimeUs)
+{
+    useDshotTelemetry = motorConfig()->useDshotTelemetry && (motorConfig()->motorPwmProtocol >= PWM_TYPE_DSHOT150);
+    edtAlwaysDecode = motorConfig()->useDshotEdt != 0;
+
+    dshotResetTelemetry();
+
+    if (!useDshotTelemetry) {
+        return;
+    }
+
+    erpmToHz = ERPM_PER_LSB / 60.0f / (motorConfig()->motorPoleCount / 2.0f);
+
+    for (unsigned i = 0; i < MAX_SUPPORTED_MOTORS; i++) {
+        pt1FilterInit(&motorFreqLpf[i], DSHOT_RPM_LPF_HZ, looptimeUs * 1e-6f);
+    }
+}
+
+uint16_t dshotProcessPacket(uint16_t rawValue, uint8_t motorIndex)
+{
+    if (!useDshotTelemetry || motorIndex >= MAX_SUPPORTED_MOTORS) {
+        return rawValue;
+    }
+
+    if (rawValue == DSHOT_TELEMETRY_INVALID || rawValue == DSHOT_TELEMETRY_NOEDGE) {
+        if (rawValue == DSHOT_TELEMETRY_INVALID) {
+            dshotTelemetryState.invalidPacketCount++;
+        }
+        return rawValue;
+    }
+
+    dshotTelemetryState.readCount++;
+    dshotTelemetryState.motorState[motorIndex].rawValue = rawValue;
+
+    dshotTelemetryType_e type;
+    uint32_t decoded;
+    dshotDecodeTelemetryValue(motorIndex, &decoded, &type);
+    if (decoded == DSHOT_TELEMETRY_INVALID) {
+        dshotTelemetryState.invalidPacketCount++;
+        return DSHOT_TELEMETRY_INVALID;
+    }
+
+    dshotTelemetryState.motorState[motorIndex].telemetryData[type] = decoded;
+    dshotTelemetryState.motorState[motorIndex].telemetryTypes |= (1 << type);
+
+    if (type == DSHOT_TELEMETRY_TYPE_TEMPERATURE && decoded > dshotTelemetryState.motorState[motorIndex].maxTemp) {
+        dshotTelemetryState.motorState[motorIndex].maxTemp = decoded;
+    }
+
+    if (type == DSHOT_TELEMETRY_TYPE_ERPM) {
+        dshotRpm[motorIndex] = erpmToRpm(decoded);
+        motorFrequencyHz[motorIndex] = pt1FilterApply(&motorFreqLpf[motorIndex], erpmToHz * decoded);
+    }
+
+    float rpmTotal = 0.0f;
+    int rpmCount = 0;
+    for (unsigned i = 0; i < getMotorCount(); i++) {
+        if (dshotTelemetryState.motorState[i].telemetryTypes & (1 << DSHOT_TELEMETRY_TYPE_ERPM)) {
+            rpmTotal += dshotRpm[i];
+            rpmCount++;
+        }
+    }
+    dshotRpmAverage = rpmCount ? rpmTotal / rpmCount : 0.0f;
+    dshotTelemetryState.rawValueState = DSHOT_RAW_VALUE_STATE_PROCESSED;
+
+    return rawValue;
+}
+
+uint16_t getDshotErpm(uint8_t motorIndex)
+{
+    return dshotTelemetryState.motorState[motorIndex].telemetryData[DSHOT_TELEMETRY_TYPE_ERPM];
+}
+
+float getDshotRpm(uint8_t motorIndex)
+{
+    return dshotRpm[motorIndex];
+}
+
+float getDshotRpmAverage(void)
+{
+    return dshotRpmAverage;
+}
+
+float getMotorFrequencyHz(uint8_t motorIndex)
+{
+    return motorFrequencyHz[motorIndex];
+}
+
+bool getDshotEscSensorData(escSensorData_t *data, uint8_t motorIndex)
+{
+    if (!useDshotTelemetry || motorIndex >= MAX_SUPPORTED_MOTORS) {
+        return false;
+    }
+
+    const dshotTelemetryMotorState_t *state = &dshotTelemetryState.motorState[motorIndex];
+    if ((state->telemetryTypes & (1 << DSHOT_TELEMETRY_TYPE_ERPM)) == 0) {
+        return false;
+    }
+
+    data->rpm = state->telemetryData[DSHOT_TELEMETRY_TYPE_ERPM];
+    data->temperature = (state->telemetryTypes & (1 << DSHOT_TELEMETRY_TYPE_TEMPERATURE)) ? state->telemetryData[DSHOT_TELEMETRY_TYPE_TEMPERATURE] : 0;
+    data->voltage = (state->telemetryTypes & (1 << DSHOT_TELEMETRY_TYPE_VOLTAGE)) ? state->telemetryData[DSHOT_TELEMETRY_TYPE_VOLTAGE] * 250 : 0;
+    data->current = (state->telemetryTypes & (1 << DSHOT_TELEMETRY_TYPE_CURRENT)) ? state->telemetryData[DSHOT_TELEMETRY_TYPE_CURRENT] * 1000 : 0;
+
+    return true;
+}
+
+#endif
+
+#ifndef USE_DSHOT
+bool useDshotTelemetry = false;
+dshotTelemetryState_t dshotTelemetryState;
+
+void initDshotTelemetry(timeUs_t looptimeUs) { UNUSED(looptimeUs); }
+void dshotResetTelemetry(void) {}
+bool isDshotTelemetryConfigured(void) { return false; }
+bool isDshotTelemetryActive(void) { return false; }
+uint16_t dshotProcessPacket(uint16_t rawValue, uint8_t motorIndex) { UNUSED(motorIndex); return rawValue; }
+float getDshotRpm(uint8_t motorIndex) { UNUSED(motorIndex); return 0.0f; }
+uint16_t getDshotErpm(uint8_t motorIndex) { UNUSED(motorIndex); return 0; }
+float getDshotRpmAverage(void) { return 0.0f; }
+float getMotorFrequencyHz(uint8_t motorIndex) { UNUSED(motorIndex); return 0.0f; }
+bool getDshotEscSensorData(escSensorData_t *data, uint8_t motorIndex) { UNUSED(data); UNUSED(motorIndex); return false; }
+#endif

src/main/drivers/dshot.h

@@ -0,0 +1,87 @@
+/*
+ * This file is part of Betaflight.
+ *
+ * Betaflight is free software. You can redistribute this software
+ * and/or modify this software under the terms of the GNU General
+ * Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * Betaflight is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software.
+ *
+ * If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "platform.h"
+
+#include "drivers/time.h"
+#include "flight/mixer.h"
+
+#include "sensors/esc_sensor.h"
+
+#define DSHOT_TELEMETRY_NOEDGE          (0xfffe)
+#define DSHOT_TELEMETRY_INVALID         (0xffff)
+
+#define MIN_GCR_EDGES                   (7)
+#define MAX_GCR_EDGES                   (22)
+
+typedef enum {
+    DSHOT_TELEMETRY_TYPE_ERPM = 0,
+    DSHOT_TELEMETRY_TYPE_TEMPERATURE,
+    DSHOT_TELEMETRY_TYPE_VOLTAGE,
+    DSHOT_TELEMETRY_TYPE_CURRENT,
+    DSHOT_TELEMETRY_TYPE_DEBUG1,
+    DSHOT_TELEMETRY_TYPE_DEBUG2,
+    DSHOT_TELEMETRY_TYPE_DEBUG3,
+    DSHOT_TELEMETRY_TYPE_STATE_EVENTS,
+    DSHOT_TELEMETRY_TYPE_COUNT
+} dshotTelemetryType_e;
+
+#define DSHOT_NORMAL_TELEMETRY_MASK     (1 << DSHOT_TELEMETRY_TYPE_ERPM)
+#define DSHOT_EXTENDED_TELEMETRY_MASK   (~DSHOT_NORMAL_TELEMETRY_MASK)
+
+typedef enum {
+    DSHOT_RAW_VALUE_STATE_INVALID = 0,
+    DSHOT_RAW_VALUE_STATE_NOT_PROCESSED,
+    DSHOT_RAW_VALUE_STATE_PROCESSED,
+} dshotRawValueState_e;
+
+typedef struct {
+    uint16_t rawValue;
+    uint16_t telemetryData[DSHOT_TELEMETRY_TYPE_COUNT];
+    uint8_t telemetryTypes;
+    uint8_t maxTemp;
+} dshotTelemetryMotorState_t;
+
+typedef struct {
+    uint32_t invalidPacketCount;
+    uint32_t readCount;
+    dshotTelemetryMotorState_t motorState[MAX_SUPPORTED_MOTORS];
+    dshotRawValueState_e rawValueState;
+} dshotTelemetryState_t;
+
+extern bool useDshotTelemetry;
+extern dshotTelemetryState_t dshotTelemetryState;
+
+void initDshotTelemetry(timeUs_t looptimeUs);
+void dshotResetTelemetry(void);
+bool isDshotTelemetryConfigured(void);
+bool isDshotTelemetryActive(void);
+uint16_t dshotProcessPacket(uint16_t rawValue, uint8_t motorIndex);
+float getDshotRpm(uint8_t motorIndex);
+uint16_t getDshotErpm(uint8_t motorIndex);
+float getDshotRpmAverage(void);
+float getMotorFrequencyHz(uint8_t motorIndex);
+bool getDshotEscSensorData(escSensorData_t *data, uint8_t motorIndex);