DSHOT timing improvements (#12709)

DSHOT timing improvements:

If DSHOT telemetry is still being received, wait (12612)
Optimise DSHOT cache management loops (12672)
Send motor data and then immediately decode prior telemetry data for bitbanged DSHOT (12685)

src/main/build/debug.c

@@ -108,4 +108,5 @@ const char * const debugModeNames[DEBUG_COUNT] = {
     "VTX_MSP",
     "GPS_DOP",
     "FAILSAFE",
+    "DSHOT_TELEMETRY_COUNTS"
 };

src/main/build/debug.h

@@ -106,6 +106,7 @@ typedef enum {
     DEBUG_VTX_MSP,
     DEBUG_GPS_DOP,
     DEBUG_FAILSAFE,
+    DEBUG_DSHOT_TELEMETRY_COUNTS,
     DEBUG_COUNT
 } debugType_e;
 

src/main/config/config.c

@@ -630,8 +630,8 @@ void validateAndFixGyroConfig(void)
         // check for looptime restrictions based on motor protocol. Motor times have safety margin
         float motorUpdateRestriction;
 
-#if defined(STM32F411xE)
-        /* If bidirectional DSHOT is being used on an F411 then force DSHOT300. The motor update restrictions then applied
+#if defined(STM32F4)|| defined(STM32G4)
+        /* If bidirectional DSHOT is being used on an F4 or G4 then force DSHOT300. The motor update restrictions then applied
          * will automatically consider the loop time and adjust pid_process_denom appropriately
          */
         if (motorConfig()->dev.useDshotTelemetry && (motorConfig()->dev.motorPwmProtocol == PWM_TYPE_DSHOT600)) {

src/main/drivers/dshot_bitbang.c

@@ -46,6 +46,16 @@
 #include "drivers/timer.h"
 
 #include "pg/motor.h"
+#include "pg/pinio.h"
+
+// DEBUG_DSHOT_TELEMETRY_COUNTS
+// 0 - Count of telemetry packets read
+// 1 - Count of missing edge
+// 2 - Count of reception not complete in time
+// 3 - Number of high bits before telemetry start
+
+// Maximum time to wait for telemetry reception to complete
+#define DSHOT_TELEMETRY_TIMEOUT 2000
 
 FAST_DATA_ZERO_INIT bbPacer_t bbPacers[MAX_MOTOR_PACERS];  // TIM1 or TIM8
 FAST_DATA_ZERO_INIT int usedMotorPacers = 0;
@@ -324,9 +334,12 @@ FAST_IRQ_HANDLER void bbDMAIrqHandler(dmaChannelDescriptor_t *descriptor)
 #ifdef USE_DSHOT_TELEMETRY
     if (useDshotTelemetry) {
         if (bbPort->direction == DSHOT_BITBANG_DIRECTION_INPUT) {
+            bbPort->telemetryPending = false;
 #ifdef DEBUG_COUNT_INTERRUPT
             bbPort->inputIrq++;
 #endif
+            // Disable DMA as telemetry reception is complete
+            bbDMA_Cmd(bbPort, DISABLE);
         } else {
 #ifdef DEBUG_COUNT_INTERRUPT
             bbPort->outputIrq++;
@@ -335,6 +348,7 @@ FAST_IRQ_HANDLER void bbDMAIrqHandler(dmaChannelDescriptor_t *descriptor)
             // Switch to input
 
             bbSwitchToInput(bbPort);
+            bbPort->telemetryPending = true;
 
             bbTIM_DMACmd(bbPort->timhw->tim, bbPort->dmaSource, ENABLE);
         }
@@ -441,7 +455,7 @@ static bool bbMotorConfig(IO_t io, uint8_t motorIndex, motorPwmProtocolTypes_e p
 
         if (!bbPort || !dmaAllocate(dmaGetIdentifier(bbPort->dmaResource), bbPort->owner.owner, bbPort->owner.resourceIndex)) {
             bbDevice.vTable.write = motorWriteNull;
-            bbDevice.vTable.updateStart = motorUpdateStartNull;
+            bbDevice.vTable.decodeTelemetry = motorDecodeTelemetryNull;
             bbDevice.vTable.updateComplete = motorUpdateCompleteNull;
 
             return false;
@@ -493,49 +507,71 @@ static bool bbMotorConfig(IO_t io, uint8_t motorIndex, motorPwmProtocolTypes_e p
     return true;
 }
 
-static bool bbUpdateStart(void)
+static bool bbTelemetryWait(void)
+{
+    // Wait for telemetry reception to complete
+    bool telemetryPending;
+    bool telemetryWait = false;
+    const timeUs_t startTimeUs = micros();
+
+    do {
+        telemetryPending = false;
+        for (int i = 0; i < usedMotorPorts; i++) {
+            telemetryPending |= bbPorts[i].telemetryPending;
+        }
+
+        telemetryWait |= telemetryPending;
+
+        if (cmpTimeUs(micros(), startTimeUs) > DSHOT_TELEMETRY_TIMEOUT) {
+            break;
+        }
+    } while (telemetryPending);
+
+    if (telemetryWait) {
+        DEBUG_SET(DEBUG_DSHOT_TELEMETRY_COUNTS, 2, debug[2] + 1);
+    }
+
+    return telemetryWait;
+}
+
+static void bbUpdateInit(void)
+{
+    for (int i = 0; i < usedMotorPorts; i++) {
+        bbOutputDataClear(bbPorts[i].portOutputBuffer);
+    }
+}
+
+static bool bbDecodeTelemetry(void)
 {
 #ifdef USE_DSHOT_TELEMETRY
     if (useDshotTelemetry) {
 #ifdef USE_DSHOT_TELEMETRY_STATS
         const timeMs_t currentTimeMs = millis();
 #endif
-        timeUs_t currentUs = micros();
 
-        // don't send while telemetry frames might still be incoming
-        if (cmpTimeUs(currentUs, lastSendUs) < (timeDelta_t)(40 + 2 * dshotFrameUs)) {
-            return false;
-        }
-
-        for (int motorIndex = 0; motorIndex < MAX_SUPPORTED_MOTORS && motorIndex < motorCount; motorIndex++) {
 #ifdef USE_DSHOT_CACHE_MGMT
-            // Only invalidate the buffer once. If all motors are on a common port they'll share a buffer.
-            bool invalidated = false;
-            for (int i = 0; i < motorIndex; i++) {
-                if (bbMotors[motorIndex].bbPort->portInputBuffer == bbMotors[i].bbPort->portInputBuffer) {
-                    invalidated = true;
-                }
-            }
-            if (!invalidated) {
-                SCB_InvalidateDCache_by_Addr((uint32_t *)bbMotors[motorIndex].bbPort->portInputBuffer,
-                                             DSHOT_BB_PORT_IP_BUF_CACHE_ALIGN_BYTES);
-            }
+        for (int i = 0; i < usedMotorPorts; i++) {
+            bbPort_t *bbPort = &bbPorts[i];
+            SCB_InvalidateDCache_by_Addr((uint32_t *)bbPort->portInputBuffer, DSHOT_BB_PORT_IP_BUF_CACHE_ALIGN_BYTES);
+        }
 #endif
-
+        for (int motorIndex = 0; motorIndex < MAX_SUPPORTED_MOTORS && motorIndex < motorCount; motorIndex++) {
 #ifdef STM32F4
             uint32_t rawValue = decode_bb_bitband(
                 bbMotors[motorIndex].bbPort->portInputBuffer,
-                bbMotors[motorIndex].bbPort->portInputCount - bbDMA_Count(bbMotors[motorIndex].bbPort),
+                bbMotors[motorIndex].bbPort->portInputCount,
                 bbMotors[motorIndex].pinIndex);
 #else
             uint32_t rawValue = decode_bb(
                 bbMotors[motorIndex].bbPort->portInputBuffer,
-                bbMotors[motorIndex].bbPort->portInputCount - bbDMA_Count(bbMotors[motorIndex].bbPort),
+                bbMotors[motorIndex].bbPort->portInputCount,
                 bbMotors[motorIndex].pinIndex);
 #endif
             if (rawValue == DSHOT_TELEMETRY_NOEDGE) {
+                DEBUG_SET(DEBUG_DSHOT_TELEMETRY_COUNTS, 1, debug[1] + 1);
                 continue;
             }
+            DEBUG_SET(DEBUG_DSHOT_TELEMETRY_COUNTS, 0, debug[0] + 1);
             dshotTelemetryState.readCount++;
 
             if (rawValue != DSHOT_TELEMETRY_INVALID) {
@@ -556,10 +592,6 @@ static bool bbUpdateStart(void)
         dshotTelemetryState.rawValueState = DSHOT_RAW_VALUE_STATE_NOT_PROCESSED;
     }
 #endif
-    for (int i = 0; i < usedMotorPorts; i++) {
-        bbDMA_Cmd(&bbPorts[i], DISABLE);
-        bbOutputDataClear(bbPorts[i].portOutputBuffer);
-    }
 
     return true;
 }
@@ -616,23 +648,11 @@ static void bbUpdateComplete(void)
         }
     }
 
-#ifdef USE_DSHOT_CACHE_MGMT
-    for (int motorIndex = 0; motorIndex < MAX_SUPPORTED_MOTORS && motorIndex < motorCount; motorIndex++) {
-        // Only clean each buffer once. If all motors are on a common port they'll share a buffer.
-        bool clean = false;
-        for (int i = 0; i < motorIndex; i++) {
-            if (bbMotors[motorIndex].bbPort->portOutputBuffer == bbMotors[i].bbPort->portOutputBuffer) {
-                clean = true;
-            }
-        }
-        if (!clean) {
-            SCB_CleanDCache_by_Addr(bbMotors[motorIndex].bbPort->portOutputBuffer, MOTOR_DSHOT_BUF_CACHE_ALIGN_BYTES);
-        }
-    }
-#endif
-
     for (int i = 0; i < usedMotorPorts; i++) {
         bbPort_t *bbPort = &bbPorts[i];
+#ifdef USE_DSHOT_CACHE_MGMT
+        SCB_CleanDCache_by_Addr(bbPort->portOutputBuffer, MOTOR_DSHOT_BUF_CACHE_ALIGN_BYTES);
+#endif
 
 #ifdef USE_DSHOT_TELEMETRY
         if (useDshotTelemetry) {
@@ -708,7 +728,9 @@ static motorVTable_t bbVTable = {
     .enable = bbEnableMotors,
     .disable = bbDisableMotors,
     .isMotorEnabled = bbIsMotorEnabled,
-    .updateStart = bbUpdateStart,
+    .telemetryWait = bbTelemetryWait,
+    .decodeTelemetry = bbDecodeTelemetry,
+    .updateInit = bbUpdateInit,
     .write = bbWrite,
     .writeInt = bbWriteInt,
     .updateComplete = bbUpdateComplete,
@@ -755,7 +777,7 @@ motorDevice_t *dshotBitbangDevInit(const motorDevConfig_t *motorConfig, uint8_t
         if (!IOIsFreeOrPreinit(io)) {
             /* not enough motors initialised for the mixer or a break in the motors */
             bbDevice.vTable.write = motorWriteNull;
-            bbDevice.vTable.updateStart = motorUpdateStartNull;
+            bbDevice.vTable.decodeTelemetry = motorDecodeTelemetryNull;
             bbDevice.vTable.updateComplete = motorUpdateCompleteNull;
             bbStatus = DSHOT_BITBANG_STATUS_MOTOR_PIN_CONFLICT;
             return NULL;

src/main/drivers/dshot_bitbang_decode.c

@@ -1,3 +1,23 @@
+/*
+ * This file is part of Cleanflight and Betaflight.
+ *
+ * Cleanflight and Betaflight are 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.
+ *
+ * Cleanflight and Betaflight are distributed in the hope that they
+ * 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 <stdint.h>
 #include <string.h>
 #include <stdio.h>
@@ -8,6 +28,7 @@
 
 #include "common/maths.h"
 #include "common/utils.h"
+#include "build/debug.h"
 #include "drivers/dshot.h"
 #include "drivers/dshot_bitbang_decode.h"
 
@@ -28,7 +49,8 @@ uint16_t bbBuffer[134];
 #define BITBAND_SRAM_BASE  0x22000000
 #define BITBAND_SRAM(a,b) ((BITBAND_SRAM_BASE + (((a)-BITBAND_SRAM_REF)<<5) + ((b)<<2)))  // Convert SRAM address
 
-
+#define DSHOT_TELEMETRY_START_MARGIN 10
+static uint8_t preambleSkip = 0;
 
 typedef struct bitBandWord_s {
     uint32_t value;
@@ -84,6 +106,8 @@ static uint32_t decode_bb_value(uint32_t value, uint16_t buffer[], uint32_t coun
 
 uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
 {
+    uint8_t startMargin;
+
 #ifdef DEBUG_BBDECODE
     memset(sequence, 0, sizeof(sequence));
     sequenceIndex = 0;
@@ -94,6 +118,9 @@ uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
     bitBandWord_t* b = p;
     bitBandWord_t* endP = p + (count - MIN_VALID_BBSAMPLES);
 
+    // Jump forward in the buffer to just before where we anticipate the first zero
+    p += preambleSkip;
+
     // Eliminate leading high signal level by looking for first zero bit in data stream.
     // Manual loop unrolling and branch hinting to produce faster code.
     while (p < endP) {
@@ -105,6 +132,9 @@ uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
         }
     }
 
+    startMargin = p - b;
+    DEBUG_SET(DEBUG_DSHOT_TELEMETRY_COUNTS, 3, startMargin);
+
     if (p >= endP) {
         // not returning telemetry is ok if the esc cpu is
         // overburdened.  in that case no edge will be found and
@@ -188,6 +218,10 @@ uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
     sequence[sequenceIndex] = sequence[sequenceIndex] + (nlen) * 3;
     sequenceIndex++;
 #endif
+
+    // The anticipated edges were observed
+    preambleSkip = startMargin - DSHOT_TELEMETRY_START_MARGIN;
+
     if (nlen > 0) {
         value <<= nlen;
         value |= 1 << (nlen - 1);
@@ -198,6 +232,8 @@ uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
 
 FAST_CODE uint32_t decode_bb( uint16_t buffer[], uint32_t count, uint32_t bit)
 {
+    uint8_t startMargin;
+
 #ifdef DEBUG_BBDECODE
     memset(sequence, 0, sizeof(sequence));
     sequenceIndex = 0;
@@ -209,12 +245,15 @@ FAST_CODE uint32_t decode_bb( uint16_t buffer[], uint32_t count, uint32_t bit)
     memset(sequence, 0, sizeof(sequence));
     int sequenceIndex = 0;
 #endif
-
     uint16_t lastValue = 0;
     uint32_t value = 0;
 
     uint16_t* p = buffer;
     uint16_t* endP = p + count - MIN_VALID_BBSAMPLES;
+
+    // Jump forward in the buffer to just before where we anticipate the first zero
+    p += preambleSkip;
+
     // Eliminate leading high signal level by looking for first zero bit in data stream.
     // Manual loop unrolling and branch hinting to produce faster code.
     while (p < endP) {
@@ -226,10 +265,15 @@ FAST_CODE uint32_t decode_bb( uint16_t buffer[], uint32_t count, uint32_t bit)
         }
     }
 
-    if(*p & mask) {
+    startMargin = p - buffer;
+    DEBUG_SET(DEBUG_DSHOT_TELEMETRY_COUNTS, 3, startMargin);
+
+    if (p >= endP) {
         // not returning telemetry is ok if the esc cpu is
         // overburdened.  in that case no edge will be found and
         // BB_NOEDGE indicates the condition to caller
+        // Increase the start margin
+        preambleSkip--;
         return DSHOT_TELEMETRY_NOEDGE;
     }
 
@@ -268,6 +312,8 @@ FAST_CODE uint32_t decode_bb( uint16_t buffer[], uint32_t count, uint32_t bit)
 
     // length of last sequence has to be inferred since the last bit with inverted dshot is high
     if (bits < 18) {
+        // Increase the start margin
+        preambleSkip--;
         return DSHOT_TELEMETRY_NOEDGE;
     }
 
@@ -278,9 +324,14 @@ FAST_CODE uint32_t decode_bb( uint16_t buffer[], uint32_t count, uint32_t bit)
 #endif
 
     if (nlen < 0) {
+        // Increase the start margin
+        preambleSkip--;
         return DSHOT_TELEMETRY_NOEDGE;
     }
 
+    // The anticipated edges were observed
+    preambleSkip = startMargin - DSHOT_TELEMETRY_START_MARGIN;
+
     if (nlen > 0) {
         value <<= nlen;
         value |= 1 << (nlen - 1);

src/main/drivers/dshot_bitbang_impl.h

@@ -167,6 +167,7 @@ typedef struct bbPort_s {
     uint16_t *portInputBuffer;
     uint32_t portInputCount;
     bool inputActive;
+    volatile bool telemetryPending;
 
     // Misc
 #ifdef DEBUG_COUNT_INTERRUPT

src/main/drivers/dshot_command.c

@@ -218,7 +218,7 @@ void dshotCommandWrite(uint8_t index, uint8_t motorCount, uint8_t command, dshot
 
 #ifdef USE_DSHOT_TELEMETRY
             timeUs_t timeoutUs = micros() + 1000;
-            while (!motorGetVTable().updateStart() &&
+            while (!motorGetVTable().decodeTelemetry() &&
                    cmpTimeUs(timeoutUs, micros()) > 0);
 #endif
             for (uint8_t i = 0; i < motorDeviceCount(); i++) {

src/main/drivers/dshot_dpwm.c

@@ -140,7 +140,7 @@ static motorVTable_t dshotPwmVTable = {
     .enable = dshotPwmEnableMotors,
     .disable = dshotPwmDisableMotors,
     .isMotorEnabled = dshotPwmIsMotorEnabled,
-    .updateStart = motorUpdateStartNull, // May be updated after copying
+    .decodeTelemetry = motorDecodeTelemetryNull, // May be updated after copying
     .write = dshotWrite,
     .writeInt = dshotWriteInt,
     .updateComplete = pwmCompleteDshotMotorUpdate,
@@ -160,7 +160,7 @@ motorDevice_t *dshotPwmDevInit(const motorDevConfig_t *motorConfig, uint16_t idl
 
 #ifdef USE_DSHOT_TELEMETRY
     useDshotTelemetry = motorConfig->useDshotTelemetry;
-    dshotPwmDevice.vTable.updateStart = pwmStartDshotMotorUpdate;
+    dshotPwmDevice.vTable.decodeTelemetry = pwmTelemetryDecode;
 #endif
 
     switch (motorConfig->motorPwmProtocol) {

src/main/drivers/dshot_dpwm.h

@@ -159,7 +159,7 @@ motorDmaOutput_t *getMotorDmaOutput(uint8_t index);
 void pwmWriteDshotInt(uint8_t index, uint16_t value);
 bool pwmDshotMotorHardwareConfig(const timerHardware_t *timerHardware, uint8_t motorIndex, uint8_t reorderedMotorIndex, motorPwmProtocolTypes_e pwmProtocolType, uint8_t output);
 #ifdef USE_DSHOT_TELEMETRY
-bool pwmStartDshotMotorUpdate(void);
+bool pwmTelemetryDecode(void);
 #endif
 void pwmCompleteDshotMotorUpdate(void);
 

src/main/drivers/motor.c

@@ -60,15 +60,49 @@ void motorWriteAll(float *values)
 {
 #ifdef USE_PWM_OUTPUT
     if (motorDevice->enabled) {
+#ifdef USE_DSHOT_BITBANG
+        if (isDshotBitbangActive(&motorConfig()->dev)) {
+            // Initialise the output buffers
+            if (motorDevice->vTable.updateInit) {
+                motorDevice->vTable.updateInit();
+            }
+
+            // Update the motor data
+            for (int i = 0; i < motorDevice->count; i++) {
+                motorDevice->vTable.write(i, values[i]);
+            }
+
+            // Don't attempt to write commands to the motors if telemetry is still being received
+            if (motorDevice->vTable.telemetryWait) {
+                (void)motorDevice->vTable.telemetryWait();
+            }
+
+            // Trigger the transmission of the motor data
+            motorDevice->vTable.updateComplete();
+
+            // Perform the decode of the last data received
+            // New data will be received once the send of motor data, triggered above, completes
 #if defined(USE_DSHOT) && defined(USE_DSHOT_TELEMETRY)
-        if (!motorDevice->vTable.updateStart()) {
-            return;
-        }
+            motorDevice->vTable.decodeTelemetry();
 #endif
-        for (int i = 0; i < motorDevice->count; i++) {
-            motorDevice->vTable.write(i, values[i]);
+        } else
+#endif
+        {
+            // Perform the decode of the last data received
+            // New data will be received once the send of motor data, triggered above, completes
+#if defined(USE_DSHOT) && defined(USE_DSHOT_TELEMETRY)
+            motorDevice->vTable.decodeTelemetry();
+#endif
+
+            // Update the motor data
+            for (int i = 0; i < motorDevice->count; i++) {
+                motorDevice->vTable.write(i, values[i]);
+            }
+
+            // Trigger the transmission of the motor data
+            motorDevice->vTable.updateComplete();
+
         }
-        motorDevice->vTable.updateComplete();
     }
 #else
     UNUSED(values);
@@ -193,7 +227,7 @@ static bool motorIsEnabledNull(uint8_t index)
     return false;
 }
 
-bool motorUpdateStartNull(void)
+bool motorDecodeTelemetryNull(void)
 {
     return true;
 }
@@ -235,7 +269,7 @@ static const motorVTable_t motorNullVTable = {
     .enable = motorEnableNull,
     .disable = motorDisableNull,
     .isMotorEnabled = motorIsEnabledNull,
-    .updateStart = motorUpdateStartNull,
+    .decodeTelemetry = motorDecodeTelemetryNull,
     .write = motorWriteNull,
     .writeInt = motorWriteIntNull,
     .updateComplete = motorUpdateCompleteNull,

src/main/drivers/motor.h

@@ -50,7 +50,9 @@ typedef struct motorVTable_s {
     bool (*enable)(void);
     void (*disable)(void);
     bool (*isMotorEnabled)(uint8_t index);
-    bool (*updateStart)(void);
+    bool (*telemetryWait)(void);
+    bool (*decodeTelemetry)(void);
+    void (*updateInit)(void);
     void (*write)(uint8_t index, float value);
     void (*writeInt)(uint8_t index, uint16_t value);
     void (*updateComplete)(void);
@@ -70,7 +72,7 @@ typedef struct motorDevice_s {
 
 void motorPostInitNull();
 void motorWriteNull(uint8_t index, float value);
-bool motorUpdateStartNull(void);
+bool motorDecodeTelemetryNull(void);
 void motorUpdateCompleteNull(void);
 
 void motorPostInit();

src/main/drivers/pwm_output.c

@@ -215,7 +215,7 @@ motorDevice_t *motorPwmDevInit(const motorDevConfig_t *motorConfig, uint16_t idl
     }
 
     motorPwmDevice.vTable.write = pwmWriteStandard;
-    motorPwmDevice.vTable.updateStart = motorUpdateStartNull;
+    motorPwmDevice.vTable.decodeTelemetry = motorDecodeTelemetryNull;
     motorPwmDevice.vTable.updateComplete = useUnsyncedPwm ? motorUpdateCompleteNull : pwmCompleteOneshotMotorUpdate;
 
     for (int motorIndex = 0; motorIndex < MAX_SUPPORTED_MOTORS && motorIndex < motorCount; motorIndex++) {

src/main/drivers/pwm_output_dshot_shared.c

@@ -176,7 +176,11 @@ static uint32_t decodeTelemetryPacket(uint32_t buffer[], uint32_t count)
 #endif
 
 #ifdef USE_DSHOT_TELEMETRY
-FAST_CODE_NOINLINE bool pwmStartDshotMotorUpdate(void)
+/**
+ * Process dshot telemetry packets before switching the channels back to outputs
+ * 
+*/
+FAST_CODE_NOINLINE bool pwmTelemetryDecode(void)
 {
     if (!useDshotTelemetry) {
         return true;

src/main/drivers/pwm_output_dshot_shared.h

@@ -59,7 +59,7 @@ void pwmDshotSetDirectionOutput(
 #endif
 );
 
-bool pwmStartDshotMotorUpdate(void);
+bool pwmTelemetryDecode(void);
 
 #endif
 #endif

src/main/target/SITL/target.c

@@ -520,7 +520,7 @@ static motorDevice_t motorPwmDevice = {
         .enable = pwmEnableMotors,
         .disable = pwmDisableMotors,
         .isMotorEnabled = pwmIsMotorEnabled,
-        .updateStart = motorUpdateStartNull,
+        .decodeTelemetry = motorDecodeTelemetryNull,
         .write = pwmWriteMotor,
         .writeInt = pwmWriteMotorInt,
         .updateComplete = pwmCompleteMotorUpdate,