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TMS570LS0714: TMS570LS0714 outputs 2 channels of complementary PWM, with 200kHz frequency and 50% duty cycle in the period of RTI interrupt

David Bai
Intellectual 1835 points
Part Number: TMS570LS0714

Dear team,

My customer's requirment is as below:

1. Output two channels of complementary PWM, with 200kHz frequency and 50% duty cycle;

2. Use CAN2TX, CAN2RX pins to output the PWM;

3. PWM is generated from GPIO level flip in the period of RTI interrupt (2.5us);

4. In their projects, they also used ADC interrupt (10us);

Currently, they set RTI and ADC interrupt as IRQ or FIQ, and the wave of RTI interrupt (yellow) and ADC interrupt(green) is as below, it seems that the interrupts influence each other.

Could you help to give a example on how to realize the 2 channels of  complementary PWM, with 200kHz frequency and 50% duty cycle in the period of RTI interrupt? Thanks a lot.

RTI_FIQ&ADC_FIQ(20u)


RTI_FIQ&ADC_IRQ



RTI_IRQ&ADC_IRQ(20u)


RTI_IRQ&ADC_FIQ(20u)


 

  • 0
    TI__Guru**** 186246 points
    Hello David,

    LS0714 has ePWM module. It is very easy to generate PWM signals with dead zone. The NHET can also be used to generate complementary PWM signals.

    What do you mean the interference between two timers? The two RTI compare interrupts can use the same counter or use different counter. These two comparators should not be interfered each other. The noise on the waveform is from the noise on the PCB.
  • 0 in reply to QJ Wang
    TI__Intellectual 1835 points

    Hi QJ,

    Appreciate your reply. That's useful.

    BTW, could you give an example of how to generate complementary PWM by NHET? Thanks very much.