betaflight/src/platform/APM32/dshot_bitbang.c

/*
 * 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 <stdint.h>
#include <math.h>
#include <string.h>

#include "platform.h"

#ifdef USE_DSHOT_BITBANG

#include "build/debug.h"
#include "build/debug_pin.h"

#include "drivers/io.h"
#include "drivers/io_impl.h"
#include "drivers/dma.h"
#include "drivers/dma_reqmap.h"
#include "drivers/dshot.h"
#include "drivers/dshot_bitbang.h"
#include "dshot_bitbang_impl.h"
#include "drivers/dshot_command.h"
#include "drivers/motor.h"
#include "drivers/nvic.h"
#include "drivers/dshot_bitbang_decode.h"
#include "drivers/time.h"
#include "drivers/timer.h"
#include "pwm_output_dshot_shared.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

// For MCUs that use MPU to control DMA coherency, there might be a performance hit
// on manipulating input buffer content especially if it is read multiple times,
// as the buffer region is attributed as not cachable.
// If this is not desirable, we should use manual cache invalidation.
#ifdef USE_DSHOT_CACHE_MGMT
#define BB_OUTPUT_BUFFER_ATTRIBUTE DMA_RW_AXI __attribute__((aligned(32)))
#define BB_INPUT_BUFFER_ATTRIBUTE  DMA_RW_AXI __attribute__((aligned(32)))
#else
#if defined(APM32F4)
#define BB_OUTPUT_BUFFER_ATTRIBUTE
#define BB_INPUT_BUFFER_ATTRIBUTE
#endif // APM32F4
#endif // USE_DSHOT_CACHE_MGMT

BB_OUTPUT_BUFFER_ATTRIBUTE uint32_t bbOutputBuffer[MOTOR_DSHOT_BUF_CACHE_ALIGN_LENGTH * MAX_SUPPORTED_MOTOR_PORTS];
BB_INPUT_BUFFER_ATTRIBUTE uint16_t bbInputBuffer[DSHOT_BB_PORT_IP_BUF_CACHE_ALIGN_LENGTH * MAX_SUPPORTED_MOTOR_PORTS];

uint8_t bbPuPdMode;
FAST_DATA_ZERO_INIT timeUs_t dshotFrameUs;

const timerHardware_t bbTimerHardware[] = {
#if defined(APM32F4)
    DEF_TIM(TMR8,  CH1, NONE,   0, 1),
    DEF_TIM(TMR8,  CH2, NONE,   0, 1),
    DEF_TIM(TMR8,  CH3, NONE,   0, 1),
    DEF_TIM(TMR8,  CH4, NONE,   0, 0),
    DEF_TIM(TMR1,  CH1, NONE,   0, 1),
    DEF_TIM(TMR1,  CH1, NONE,   0, 2),
    DEF_TIM(TMR1,  CH2, NONE,   0, 1),
    DEF_TIM(TMR1,  CH3, NONE,   0, 1),
    DEF_TIM(TMR1,  CH4, NONE,   0, 0),

#else
#error MCU dependent code required
#endif
};

static FAST_DATA_ZERO_INIT timeUs_t lastSendUs;

static motorProtocolTypes_e motorProtocol;

// DMA GPIO output buffer formatting

static void bbOutputDataInit(uint32_t *buffer, uint16_t portMask, bool inverted)
{
    uint32_t resetMask;
    uint32_t setMask;

    if (inverted) {
        resetMask = portMask;
        setMask = (portMask << 16);
    } else {
        resetMask = (portMask << 16);
        setMask = portMask;
    }

    int symbol_index;

    for (symbol_index = 0; symbol_index < MOTOR_DSHOT_FRAME_BITS; symbol_index++) {
        buffer[symbol_index * MOTOR_DSHOT_STATE_PER_SYMBOL + 0] |= setMask ; // Always set all ports
        buffer[symbol_index * MOTOR_DSHOT_STATE_PER_SYMBOL + 1] = 0;          // Reset bits are port dependent
        buffer[symbol_index * MOTOR_DSHOT_STATE_PER_SYMBOL + 2] |= resetMask; // Always reset all ports
    }

    //
    // output one more 'bit' that keeps the line level at idle to allow the ESC to sample the last bit
    //
    // Avoid CRC errors in the case of bi-directional d-shot.  CRC errors can occur if the output is
    // transitioned to an input before the signal has been sampled by the ESC as the sampled voltage
    // may be somewhere between logic-high and logic-low depending on how the motor output line is
    // driven or floating.  On some MCUs it's observed that the voltage momentarily drops low on transition
    // to input.

    int hold_bit_index = MOTOR_DSHOT_FRAME_BITS * MOTOR_DSHOT_STATE_PER_SYMBOL;
    buffer[hold_bit_index + 0] |= resetMask; // Always reset all ports
    buffer[hold_bit_index + 1] = 0;          // Never any change
    buffer[hold_bit_index + 2] = 0;          // Never any change
}

static void bbOutputDataSet(uint32_t *buffer, int pinNumber, uint16_t value, bool inverted)
{
    uint32_t middleBit;

    if (inverted) {
        middleBit = (1 << (pinNumber + 0));
    } else {
        middleBit = (1 << (pinNumber + 16));
    }

    for (int pos = 0; pos < 16; pos++) {
        if (!(value & 0x8000)) {
            buffer[pos * 3 + 1] |= middleBit;
        }
        value <<= 1;
    }
}

static void bbOutputDataClear(uint32_t *buffer)
{
    // Middle position to no change
    for (int bitpos = 0; bitpos < 16; bitpos++) {
        buffer[bitpos * 3 + 1] = 0;
    }
}

// bbPacer management

static bbPacer_t *bbFindMotorPacer(TIM_TypeDef *tim)
{
    for (int i = 0; i < MAX_MOTOR_PACERS; i++) {

        bbPacer_t *bbPacer = &bbPacers[i];

        if (bbPacer->tim == NULL) {
            bbPacer->tim = tim;
            ++usedMotorPacers;
            return bbPacer;
        }

        if (bbPacer->tim == tim) {
            return bbPacer;
        }
    }

    return NULL;
}

// bbPort management

static bbPort_t *bbFindMotorPort(int portIndex)
{
    for (int i = 0; i < usedMotorPorts; i++) {
        if (bbPorts[i].portIndex == portIndex) {
            return &bbPorts[i];
        }
    }
    return NULL;
}

static bbPort_t *bbAllocateMotorPort(int portIndex)
{
    if (usedMotorPorts >= MAX_SUPPORTED_MOTOR_PORTS) {
        bbStatus = DSHOT_BITBANG_STATUS_TOO_MANY_PORTS;
        return NULL;
    }

    bbPort_t *bbPort = &bbPorts[usedMotorPorts];

    if (!bbPort->timhw) {
        // No more pacer channel available
        bbStatus = DSHOT_BITBANG_STATUS_NO_PACER;
        return NULL;
    }

    bbPort->portIndex = portIndex;
    bbPort->owner.owner = OWNER_DSHOT_BITBANG;
    bbPort->owner.resourceIndex = RESOURCE_INDEX(portIndex);

    ++usedMotorPorts;

    return bbPort;
}

const timerHardware_t *dshotBitbangTimerGetAllocatedByNumberAndChannel(int8_t timerNumber, uint16_t timerChannel)
{
    for (int index = 0; index < usedMotorPorts; index++) {
        const timerHardware_t *bitbangTimer = bbPorts[index].timhw;
        if (bitbangTimer && timerGetTIMNumber(bitbangTimer->tim) == timerNumber && bitbangTimer->channel == timerChannel && bbPorts[index].owner.owner) {
            return bitbangTimer;
        }
    }

    return NULL;
}

const resourceOwner_t *dshotBitbangTimerGetOwner(const timerHardware_t *timer)
{
    for (int index = 0; index < usedMotorPorts; index++) {
        const timerHardware_t *bitbangTimer = bbPorts[index].timhw;
        if (bitbangTimer && bitbangTimer == timer) {
            return &bbPorts[index].owner;
        }
    }

    return &freeOwner;
}

// Return frequency of smallest change [state/sec]

static uint32_t getDshotBaseFrequency(motorProtocolTypes_e pwmProtocolType)
{
    switch (pwmProtocolType) {
    case(MOTOR_PROTOCOL_DSHOT600):
        return MOTOR_DSHOT600_SYMBOL_RATE * MOTOR_DSHOT_STATE_PER_SYMBOL;
    case(MOTOR_PROTOCOL_DSHOT300):
        return MOTOR_DSHOT300_SYMBOL_RATE * MOTOR_DSHOT_STATE_PER_SYMBOL;
    default:
    case(MOTOR_PROTOCOL_DSHOT150):
        return MOTOR_DSHOT150_SYMBOL_RATE * MOTOR_DSHOT_STATE_PER_SYMBOL;
    }
}

static void bbSetupDma(bbPort_t *bbPort)
{
    const dmaIdentifier_e dmaIdentifier = dmaGetIdentifier(bbPort->dmaResource);
    dmaEnable(dmaIdentifier);
    bbPort->dmaSource = timerDmaSource(bbPort->timhw->channel);

    bbPacer_t *bbPacer = bbFindMotorPacer(bbPort->timhw->tim);
    bbPacer->dmaSources |= bbPort->dmaSource;

    dmaSetHandler(dmaIdentifier, bbDMAIrqHandler, NVIC_BUILD_PRIORITY(2, 1), (uint32_t)bbPort);

    bbDMA_ITConfig(bbPort);
}

FAST_IRQ_HANDLER void bbDMAIrqHandler(dmaChannelDescriptor_t *descriptor)
{
    dbgPinHi(0);

    bbPort_t *bbPort = (bbPort_t *)descriptor->userParam;

    bbDMA_Cmd(bbPort, DISABLE);

    bbTIM_DMACmd(bbPort->timhw->tim, bbPort->dmaSource, DISABLE);

    if (DMA_GET_FLAG_STATUS(descriptor, DMA_IT_TEIF)) {
        while (1) {};
    }

    DMA_CLEAR_FLAG(descriptor, DMA_IT_TCIF);

#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++;
#endif

            // Switch to input

            bbSwitchToInput(bbPort);
            bbPort->telemetryPending = true;

            bbTIM_DMACmd(bbPort->timhw->tim, bbPort->dmaSource, ENABLE);
        }
    }
#endif
    dbgPinLo(0);
}

// Setup bbPorts array elements so that they each have a TIM1 or TIM8 channel
// in timerHardware array for BB-DShot.

static void bbFindPacerTimer(void)
{
    for (int bbPortIndex = 0; bbPortIndex < MAX_SUPPORTED_MOTOR_PORTS; bbPortIndex++) {
        for (unsigned timerIndex = 0; timerIndex < ARRAYLEN(bbTimerHardware); timerIndex++) {
            const timerHardware_t *timer = &bbTimerHardware[timerIndex];
            int timNumber = timerGetTIMNumber(timer->tim);
            if ((motorConfig()->dev.useDshotBitbangedTimer == DSHOT_BITBANGED_TIMER_TIM1 && timNumber != 1)
                || (motorConfig()->dev.useDshotBitbangedTimer == DSHOT_BITBANGED_TIMER_TIM8 && timNumber != 8)) {
                continue;
            }
            bool timerConflict = false;
            for (int channel = 0; channel < CC_CHANNELS_PER_TIMER; channel++) {
                const timerHardware_t *timer = timerGetAllocatedByNumberAndChannel(timNumber, CC_CHANNEL_FROM_INDEX(channel));
                const resourceOwner_e timerOwner = timerGetOwner(timer)->owner;
                if (timerOwner != OWNER_FREE && timerOwner != OWNER_DSHOT_BITBANG) {
                    timerConflict = true;
                    break;
                }
            }

            for (int index = 0; index < bbPortIndex; index++) {
                const timerHardware_t* t = bbPorts[index].timhw;
                if (timerGetTIMNumber(t->tim) == timNumber && timer->channel == t->channel) {
                    timerConflict = true;
                    break;
                }
            }

            if (timerConflict) {
                continue;
            }

#ifdef USE_DMA_SPEC
            dmaoptValue_t dmaopt = dmaGetOptionByTimer(timer);
            const dmaChannelSpec_t *dmaChannelSpec = dmaGetChannelSpecByTimerValue(timer->tim, timer->channel, dmaopt);
            dmaResource_t *dma = dmaChannelSpec->ref;
#else
            dmaResource_t *dma = timer->dmaRef;
#endif
            dmaIdentifier_e dmaIdentifier = dmaGetIdentifier(dma);
            if (dmaGetOwner(dmaIdentifier)->owner == OWNER_FREE) {
                bbPorts[bbPortIndex].timhw = timer;

                break;
            }
        }
    }
}

static void bbTimebaseSetup(bbPort_t *bbPort, motorProtocolTypes_e dshotProtocolType)
{
    uint32_t timerclock = timerClock(bbPort->timhw->tim);

    uint32_t outputFreq = getDshotBaseFrequency(dshotProtocolType);
    dshotFrameUs = 1000000 * 17 * 3 / outputFreq;
    bbPort->outputARR = timerclock / outputFreq - 1;

    // XXX Explain this formula
    uint32_t inputFreq = outputFreq * 5 * 2 * DSHOT_BITBANG_TELEMETRY_OVER_SAMPLE / 24;
    bbPort->inputARR = timerclock / inputFreq - 1;
}

//
// bb only use pin info associated with timerHardware entry designated as TIM_USE_MOTOR;
// it does not use the timer channel associated with the pin.
//

static bool bbMotorConfig(IO_t io, uint8_t motorIndex, motorProtocolTypes_e pwmProtocolType, uint8_t output)
{
    // Return if no GPIO is specified
    if (!io) {
        return false;
    }

    int pinIndex = IO_GPIOPinIdx(io);
    int portIndex = IO_GPIOPortIdx(io);

    bbPort_t *bbPort = bbFindMotorPort(portIndex);

    if (!bbPort) {

        // New port group

        bbPort = bbAllocateMotorPort(portIndex);

        if (bbPort) {
            const timerHardware_t *timhw = bbPort->timhw;

#ifdef USE_DMA_SPEC
            const dmaChannelSpec_t *dmaChannelSpec = dmaGetChannelSpecByTimerValue(timhw->tim, timhw->channel, dmaGetOptionByTimer(timhw));
            bbPort->dmaResource = dmaChannelSpec->ref;
            bbPort->dmaChannel = dmaChannelSpec->channel;
#else
            bbPort->dmaResource = timhw->dmaRef;
            bbPort->dmaChannel = timhw->dmaChannel;
#endif
        }

        if (!bbPort || !dmaAllocate(dmaGetIdentifier(bbPort->dmaResource), bbPort->owner.owner, bbPort->owner.resourceIndex)) {
            return false;
        }

        bbPort->gpio = IO_GPIO(io);

        bbPort->portOutputCount = MOTOR_DSHOT_BUF_LENGTH;
        bbPort->portOutputBuffer = &bbOutputBuffer[(bbPort - bbPorts) * MOTOR_DSHOT_BUF_CACHE_ALIGN_LENGTH];

        bbPort->portInputCount = DSHOT_BB_PORT_IP_BUF_LENGTH;
        bbPort->portInputBuffer = &bbInputBuffer[(bbPort - bbPorts) * DSHOT_BB_PORT_IP_BUF_CACHE_ALIGN_LENGTH];

        bbTimebaseSetup(bbPort, pwmProtocolType);
        bbTIM_TimeBaseInit(bbPort, bbPort->outputARR);
        bbTimerChannelInit(bbPort);

        bbSetupDma(bbPort);
        bbDMAPreconfigure(bbPort, DSHOT_BITBANG_DIRECTION_OUTPUT);
        bbDMAPreconfigure(bbPort, DSHOT_BITBANG_DIRECTION_INPUT);

        bbDMA_ITConfig(bbPort);
    }

    bbMotors[motorIndex].pinIndex = pinIndex;
    bbMotors[motorIndex].io = io;
    bbMotors[motorIndex].output = output;
    bbMotors[motorIndex].bbPort = bbPort;

    IOInit(io, OWNER_MOTOR, RESOURCE_INDEX(motorIndex));

    // Setup GPIO_MODER and GPIO_ODR register manipulation values

    bbGpioSetup(&bbMotors[motorIndex]);

    do {
#ifdef USE_DSHOT_TELEMETRY
    if (useDshotTelemetry) {
        bbOutputDataInit(bbPort->portOutputBuffer, (1 << pinIndex), DSHOT_BITBANG_INVERTED);
        break;
    }
#endif
        bbOutputDataInit(bbPort->portOutputBuffer, (1 << pinIndex), DSHOT_BITBANG_NONINVERTED);
    } while (false);

    bbSwitchToOutput(bbPort);

    bbMotors[motorIndex].configured = true;

    return true;
}

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

#ifdef USE_DSHOT_CACHE_MGMT
        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 < dshotMotorCount; motorIndex++) {
#ifdef APM32F4
            uint32_t rawValue = decode_bb_bitband(
                bbMotors[motorIndex].bbPort->portInputBuffer,
                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) {
                // Check EDT enable or store raw value
                if ((rawValue == 0x0E00) && (dshotCommandGetCurrent(motorIndex) == DSHOT_CMD_EXTENDED_TELEMETRY_ENABLE)) {
                    dshotTelemetryState.motorState[motorIndex].telemetryTypes = 1 << DSHOT_TELEMETRY_TYPE_STATE_EVENTS;
                } else {
                    dshotTelemetryState.motorState[motorIndex].rawValue = rawValue;
                }
            } else {
                dshotTelemetryState.invalidPacketCount++;
            }
#ifdef USE_DSHOT_TELEMETRY_STATS
            updateDshotTelemetryQuality(&dshotTelemetryQuality[motorIndex], rawValue != DSHOT_TELEMETRY_INVALID, currentTimeMs);
#endif
        }

        dshotTelemetryState.rawValueState = DSHOT_RAW_VALUE_STATE_NOT_PROCESSED;
    }
#endif

    return true;
}

static void bbWriteInt(uint8_t motorIndex, uint16_t value)
{
    bbMotor_t *const bbmotor = &bbMotors[motorIndex];

    if (!bbmotor->configured) {
        return;
    }

    // fetch requestTelemetry from motors. Needs to be refactored.
    motorDmaOutput_t * const motor = getMotorDmaOutput(motorIndex);
    bbmotor->protocolControl.requestTelemetry = motor->protocolControl.requestTelemetry;
    motor->protocolControl.requestTelemetry = false;

    // If there is a command ready to go overwrite the value and send that instead
    if (dshotCommandIsProcessing()) {
        value = dshotCommandGetCurrent(motorIndex);
        if (value) {
            bbmotor->protocolControl.requestTelemetry = true;
        }
    }

    bbmotor->protocolControl.value = value;

    uint16_t packet = prepareDshotPacket(&bbmotor->protocolControl);

    bbPort_t *bbPort = bbmotor->bbPort;

    do {
#ifdef USE_DSHOT_TELEMETRY
        if (useDshotTelemetry) {
            bbOutputDataSet(bbPort->portOutputBuffer, bbmotor->pinIndex, packet, DSHOT_BITBANG_INVERTED);
            break;
        }
#endif
        bbOutputDataSet(bbPort->portOutputBuffer, bbmotor->pinIndex, packet, DSHOT_BITBANG_NONINVERTED);
    } while (false);
}

static void bbWrite(uint8_t motorIndex, float value)
{
    bbWriteInt(motorIndex, lrintf(value));
}

static void bbUpdateComplete(void)
{
    // If there is a dshot command loaded up, time it correctly with motor update

    if (!dshotCommandQueueEmpty()) {
        if (!dshotCommandOutputIsEnabled(dshotMotorCount)) {
            return;
        }
    }

    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) {
            if (bbPort->direction == DSHOT_BITBANG_DIRECTION_INPUT) {
                bbPort->inputActive = false;
                bbSwitchToOutput(bbPort);
            }
        }
#endif

        bbDMA_Cmd(bbPort, ENABLE);
    }

    lastSendUs = micros();
    for (int i = 0; i < usedMotorPacers; i++) {
        bbPacer_t *bbPacer = &bbPacers[i];
        bbTIM_DMACmd(bbPacer->tim, bbPacer->dmaSources, ENABLE);
    }
}

static bool bbEnableMotors(void)
{
    for (int i = 0; i < dshotMotorCount; i++) {
        if (bbMotors[i].configured) {
            IOConfigGPIO(bbMotors[i].io, bbMotors[i].iocfg);
        }
    }
    return true;
}

static void bbDisableMotors(void)
{
    return;
}

static void bbShutdown(void)
{
    return;
}

static bool bbIsMotorEnabled(unsigned index)
{
    return bbMotors[index].enabled;
}

static void bbPostInit(void)
{
    bbFindPacerTimer();

    for (int motorIndex = 0; motorIndex < MAX_SUPPORTED_MOTORS && motorIndex < dshotMotorCount; motorIndex++) {

        if (!bbMotorConfig(bbMotors[motorIndex].io, motorIndex, motorProtocol, bbMotors[motorIndex].output)) {
            return;
        }

        bbMotors[motorIndex].enabled = true;
    }
}

static motorVTable_t bbVTable = {
    .postInit = bbPostInit,
    .enable = bbEnableMotors,
    .disable = bbDisableMotors,
    .isMotorEnabled = bbIsMotorEnabled,
    .telemetryWait = bbTelemetryWait,
    .decodeTelemetry = bbDecodeTelemetry,
    .updateInit = bbUpdateInit,
    .write = bbWrite,
    .writeInt = bbWriteInt,
    .updateComplete = bbUpdateComplete,
    .convertExternalToMotor = dshotConvertFromExternal,
    .convertMotorToExternal = dshotConvertToExternal,
    .shutdown = bbShutdown,
    .isMotorIdle = bbDshotIsMotorIdle,
    .requestTelemetry = bbDshotRequestTelemetry,
    .getMotorIO = bbGetMotorIO,
};

dshotBitbangStatus_e dshotBitbangGetStatus(void)
{
    return bbStatus;
}

bool dshotBitbangDevInit(motorDevice_t *device, const motorDevConfig_t *motorConfig)
{
    dbgPinLo(0);
    dbgPinLo(1);

    if (!device || !motorConfig) {
        return false;
    }

    motorProtocol = motorConfig->motorProtocol;
    device->vTable = &bbVTable;
    dshotMotorCount = device->count;
    bbStatus = DSHOT_BITBANG_STATUS_OK;

#ifdef USE_DSHOT_TELEMETRY
    useDshotTelemetry = motorConfig->useDshotTelemetry;
#endif

    memset(bbOutputBuffer, 0, sizeof(bbOutputBuffer));

    for (int motorIndex = 0; motorIndex < MAX_SUPPORTED_MOTORS && motorIndex < dshotMotorCount; motorIndex++) {
        const unsigned reorderedMotorIndex = motorConfig->motorOutputReordering[motorIndex];
        const timerHardware_t *timerHardware = timerGetConfiguredByTag(motorConfig->ioTags[reorderedMotorIndex]);
        const IO_t io = IOGetByTag(motorConfig->ioTags[reorderedMotorIndex]);

        uint8_t output = motorConfig->motorInversion ?  timerHardware->output ^ TIMER_OUTPUT_INVERTED : timerHardware->output;
        bbPuPdMode = (output & TIMER_OUTPUT_INVERTED) ? BB_GPIO_PULLDOWN : BB_GPIO_PULLUP;

#ifdef USE_DSHOT_TELEMETRY
        if (useDshotTelemetry) {
            output ^= TIMER_OUTPUT_INVERTED;
        }
#endif

        if (!IOIsFreeOrPreinit(io)) {
            /* not enough motors initialised for the mixer or a break in the motors */
            device->vTable = NULL;
            dshotMotorCount = 0;
            bbStatus = DSHOT_BITBANG_STATUS_MOTOR_PIN_CONFLICT;
            return false;
        }

        int pinIndex = IO_GPIOPinIdx(io);

        bbMotors[motorIndex].pinIndex = pinIndex;
        bbMotors[motorIndex].io = io;
        bbMotors[motorIndex].output = output;
#if defined(APM32F4)
        bbMotors[motorIndex].iocfg = IO_CONFIG(GPIO_MODE_OUTPUT_PP, GPIO_SPEED_FREQ_LOW, bbPuPdMode);
#endif

        IOInit(io, OWNER_MOTOR, RESOURCE_INDEX(motorIndex));
        IOConfigGPIO(io, bbMotors[motorIndex].iocfg);
        if (output & TIMER_OUTPUT_INVERTED) {
            IOLo(io);
        } else {
            IOHi(io);
        }
    }
    return true;
}

#endif // USE_DSHOT_BITBANG