Short Circuit Protection

Nikhil Bapat

Other Parts Discussed in Thread: DRV8301

I am running lab 5b for the F2802x FOC chip. I have modified the system to include external on/off switch and a short circuit protection circuit. The short circuit protection circuit makes the GPIO pin 17 low for about 30 ms. Whenever this happens I want the motor to shut down so I added the following code to the 5b code:

// My variables

bool gOnOff;

bool gSckt

#define JED_GPIO_SW1 GPIO_Number_7 // External on off switch

#degine JED_GPIO_SW# GPIO_Number_17 // Short Circuit protection

for (;;)

{

//My Code

gOnOff = HAL_readGpio(halHandle, JED_GPIO_SW1); // On off switch

gSckt = HAL_readGpio(halHandle, JED_GPIO_SW3); // Short CIrcuit

if (gOnOff == true)

{

gMotorvars.Flag_Run_Identify = false;

gMotorvars.Flag_enableSys = false;

}

if (gOnOff == flase && gSckt == false)

{

HAL_disablePwm(halHandle);

gMotorvars.Flag_Run_Identify = false;

gMotorvars.Flag_enableSys = false;

}

if (gOnOff == false && gSckt == true)

{

gMotorvars.Flag_Run_Identify = true;

gMotorvars.Flag_enableSys = true;

}

// End of my code

In this code the on off part seems to be working fine, but the short circuit protection is not working. I suspect that the system gets disabled for the duration that the pin is low and comes back up as soon as the pin becomes high, which I don't want. How can I rectify this issue?

over 10 years ago

0 ChrisClearman over 10 years ago

TI__Guru** 119480 points

I don't understand...why are you not just using the Trip Zone feature of GPIO17 as is done in the project for the DRV8301 EVM?

// SPI-SOMI or FAULTn
GPIO_setMode(obj->gpioHandle,GPIO_Number_17,GPIO_17_Mode_TZ3_NOT);

HAL_setupFaults

also, you have a typo
#degine

0 Nikhil Bapat over 10 years ago in reply to ChrisClearman

Intellectual 860 points

Chris, thanks for the help :-)

I just started working with microcontrollers, so I simply did not know about the trip feature. What I was trying to do was, in the lab5b.c file, I wanted to trap the process in a small infinite loop where the two flags will be disabled. But obviously it did not work. I will try the method you suggested.

Also the typo was because I had to type the code into the sandbox here, I don't have access to internet on my work computer.

0 Nikhil Bapat over 10 years ago in reply to ChrisClearman

Intellectual 860 points

Chris,

This may be another stupid question, but can you point me to where I can get more info about the trip zone feature? I also read somewhere that the HAL can support heating and I2t protections, but now I cannot find it among all the PDFs that I got.

If you can please let me know, that would be awesome.

0 ChrisClearman over 10 years ago in reply to Nikhil Bapat

TI__Guru** 119480 points

spruge9

0 Nikhil Bapat over 10 years ago in reply to ChrisClearman

Intellectual 860 points

Chris,
Based on spruge9 and some of the previous discussions on the forum I have done the following modifications to the code:

in hal.c
void HAL_setupFaults(HAL_Handle handle)
{
HAL_Obj *obj = (HAL_Obj *)handle;
uint_least8_t cnt;

for(cnt=0;cnt<3;cnt++)
{
PWM_enableTripZoneSrc(obj->pwmHandle[cnt],PWM_TripZoneSrc_CycleByCycle_TZ6_NOT);

PWM_enableTripZoneSrc(obj->pwmHandle[cnt],PWM_TripZoneSrc_CycleByCycle_TZ2_NOT);

//PWM_enableTripZoneSrc(obj->pwmHandle[cnt],PWM_TripZoneSrc_CycleByCycle_TZ3_NOT);

PWM_enableTripZoneSrc(obj->pwmHandle[cnt],PWM_TripZoneSrc_OneShot_TZ3_NOT);

// What do we want the OST/CBC events to do?
// TZA events can force EPWMxA
// TZB events can force EPWMxB

PWM_setTripZoneState_TZA(obj->pwmHandle[cnt],PWM_TripZoneState_EPWM_Low);
PWM_setTripZoneState_TZB(obj->pwmHandle[cnt],PWM_TripZoneState_EPWM_Low);
}
...
...
GPIO_setPullUp(myGpio, GPIO_Number_17, GPIO_PullUp_Enable);
GPIO_setQualification(myGpio, GPIO_Number_17, GPIO_Qual_ASync);
GPIO_setMode(myGpio, GPIO_Number_17, GPIO_17_Mode_TZ3_NOT);

But it is still not working. What am I missing here?

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Short Circuit Protection