HET Issue: Cannot stop pwm output, if duty cycle was set to 100%

Emmanuel Dhollande

Other Parts Discussed in Thread: HALCOGEN

Hello,

I am using the pwm generation on the TMS570 platform using the HET module. I generate the code using HAlcogen (version 03.03.01).

The pwm generation works so far, however if Ithe duty cycle was set before to 100% (pwmSetDuty()) , calling the method pwmstop from the generated het.c does not deactivate the output.

For any other pwm duty cycle, I can stop the pwm generation, and the output on my pin is low.

Should I explicitely set the pin to low, after having called the pwmStop method ?

Thanks an regards

Emmanuel

over 10 years ago

0 Zhaohong Zhang over 10 years ago

TI__Mastermind 22715 points

Emmanuel,

When you set the duty cycle to 100%, the pin is stuck at high. You will have to either force the pin low after stopping PWM or reduce the duty cycle <100% before stopping.

Thanks and regards,

Zhaohong

0 Hakan AVCI over 10 years ago in reply to Zhaohong Zhang

Intellectual 255 points

Hello Zhaohong

Is this issue related to halcogen or is it related to het. Do I get same behavior if i use direct accest het assembler generated code.

In my case,I use HalcoGen 03.05.00, CCS 5.3.00090 and Hecules TMX570LS0432 HDK and I cannot set the pwm duty to zero if I ever set it to something else. I can get anything betwwen 1%-100% anytime but cannot get 0%.

regards.

0 Zhaohong Zhang over 10 years ago in reply to Hakan AVCI

TI__Mastermind 22715 points

Hakan,

For 0% duty cycle. You need to force the pin low. You need to set a special case in your programming.

Thanks and regards,

Zhaohong

0 Hakan AVCI over 10 years ago in reply to Zhaohong Zhang

Intellectual 255 points

OK, i will implement that.

Thank you.

Regards

0 Anthony F. Seely over 10 years ago in reply to Hakan AVCI

TI__Guru 65630 points

Just thought I should add a clarification that this answer is specific to the N2HET program that comes with HalCoGen which is more like a 'sampler' - it does a little bit of each type of timer function you might want.

You definitely can write a different PWM program for HET where you do not need to modify GIO to set the duty cycle to 100% or 0%. Some examples you might try are on this post:

http://e2e.ti.com/support/microcontrollers/hercules/f/312/p/284151/993513.aspx#993513

Arm-based microcontrollers

Arm-based microcontrollers forum

HET Issue: Cannot stop pwm output, if duty cycle was set to 100%