brake function in 6-steps

[Xavier75]

Hello,

I am currently designing an ESC for a small vehicle (around 300g).  I made a first proto board and I use the 6-steps algorithm with an hall sensored motor. I would like to be able to brake. I firstly thought to short all the phases directly to the ground with a PWM in order to brake more or less but it seems that there is no dedicated function  for braking in the generated project.

Here are the availabe functions in mc_api.h :

/* Starts Motor 1 */
bool MC_StartMotor1(void);

/* Stops Motor 1 */
bool MC_StopMotor1(void);

/* Programs a Speed ramp for Motor 1 */
void MC_ProgramSpeedRampMotor1(int16_t hFinalSpeed, uint16_t hDurationms);

/* Returns the current PWM duty cycle reference for Motor 1 */
int16_t MCI_GetDutyCycleRefMotor1(void);

/* Returns the state of the last submited command for Motor 1 */
MCI_CommandState_t MC_GetCommandStateMotor1(void);

/* Stops the execution of the current speed ramp for Motor 1 if any */
bool MC_StopSpeedRampMotor1(void);

/* Stops the execution of the on going ramp for Motor 1 if any.
   Note: this function is deprecated and should not be used anymore. It will be removed in a future version. */
void MC_StopRampMotor1(void);

/* Returns true if the last submited ramp for Motor 1 has completed, false otherwise */
bool MC_HasRampCompletedMotor1(void);

/* Returns the current mechanical rotor speed reference set for Motor 1, expressed in the unit defined by #SPEED_UNIT */
int16_t MC_GetMecSpeedReferenceMotor1(void);

/* Returns the current mechanical rotor speed reference set for Motor 1, expressed in rpm */
float_t MC_GetMecSpeedReferenceMotor1_F(void);

/* Returns the last computed average mechanical rotor speed for Motor 1, expressed in the unit defined by #SPEED_UNIT */
int16_t MC_GetMecSpeedAverageMotor1(void);

/* Returns the last computed average mechanical rotor speed for Motor 1, expressed in rpm */
float_t MC_GetAverageMecSpeedMotor1_F(void);

/* Returns the final speed of the last ramp programmed for Motor 1, if this ramp was a speed ramp */
int16_t MC_GetLastRampFinalSpeedMotor1(void);

/* Returns the final speed of the last ramp programmed for Motor 1, if this ramp was a speed ramp */
float_t MC_GetLastRampFinalSpeedM1_F(void);
/* Returns the current Control Mode for Motor 1 (either Speed or Torque) */
MC_ControlMode_t MC_GetControlModeMotor1(void);

/* Returns the direction imposed by the last command on Motor 1 */
int16_t MC_GetImposedDirectionMotor1(void);

/* Returns the current reliability of the speed sensor used for Motor 1 */
bool MC_GetSpeedSensorReliabilityMotor1(void);

/* Acknowledge a Motor Control fault on Motor 1 */
bool MC_AcknowledgeFaultMotor1(void);

/* Returns a bitfiled showing faults that occured since the State Machine of Motor 1 was moved to FAULT_NOW state */
uint16_t MC_GetOccurredFaultsMotor1(void);

/* Returns a bitfield showing all current faults on Motor 1 */
uint16_t MC_GetCurrentFaultsMotor1(void);

/* returns the current state of Motor 1 state machine */
MCI_State_t  MC_GetSTMStateMotor1(void);

/* Call the Profiler command */
uint8_t MC_ProfilerCommand (uint16_t rxLength, uint8_t *rxBuffer, int16_t txSyncFreeSpace, uint16_t *txLength, uint8_t *txBuffer);

What is the best way to brake ? Is it mandatory to add the load resistor ? In the commercial ESC for RC cars, there is a brake function but it doesn't seem to have a load resistor.

If I make a negative speed ramp, is it going to brake ? Or it is just decelerate with the inertia ?

Thanks for your help.

Xavier