FOC control PWM setup in DRV8301LS12 Evaluation kit... TMS570LS1227

rathinavel j

Hi,

I am using DRV8301LS12 evaluation kit.

When I look the sample code for FOC comes along with the kit.

They have implemented 20KHz PWM and PWM TBCLOCK is 80MHz.

In PWM period register, instead of 4000/2 (half period value as UPdown counter mode is used), its entered with value(3900/2).

Is there any specific reason for this implementation?

Thanks & Regards,

Rathinavel

over 11 years ago

0 Enrique Lizarraga over 11 years ago

TI__Expert 4580 points

Hello:

We will forward your post to the expert and he'll be back soon to support you.

Regards.

0 rathinavel j over 11 years ago in reply to Enrique Lizarraga

Intellectual 645 points

Hi,

Thanks for forwading.

Just to avoid confusion, I am just writing the exact code and exact value of the TBPRD register.

void DRV_setupPwms(DRV_Handle handle, const float32_t ISRperiod, const int32_t het_vCNT_SCALE)
{
DRV_Obj *obj = (DRV_Obj *)handle;
uint16_t halfPeriod_cycles = ((ISRperiod*het_vCNT_SCALE)/2)*128;
uint8_t cnt;

In the above code ISRperiod=0.00005 ( time correspond to 20KHZ), het_vCNT_SCALE=610000, so halfPeriod_cycles =3904/2=1952 ( this value is written to TBPRD)

Thanks & Regards,

Rathinavel

0 Sunil Oak over 11 years ago in reply to rathinavel j

TI__Mastermind 49120 points

Hi Rathinavel,

The engineer who wrote this demo program has left the organization. I looked into the code and could not identify any reason why the het_vCNT_SCALE value was not calculated for an 80MHz TBCLK.

I will continue to look into this and let you know.

Regards, Sunil

0 rathinavel j over 11 years ago in reply to Sunil Oak

Intellectual 645 points

ok thank you.

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FOC control PWM setup in DRV8301LS12 Evaluation kit... TMS570LS1227