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TMS320F280049C: Understanding ADC trigger and PWM

Rushi Jariwala
Expert 1225 points
Part Number: TMS320F280049C
Other Parts Discussed in Thread: MOTORWARE, C2000WARE

Hi,

I am using F280049 for motor control application. I understand that the ADCs are triggered based on ePWM module. I wanted to understand it more in detail and I have a few queries.

The first requirement is: To simultaneously measure currents, we need to trigger all the ADCs together. These ADCs are configured to be triggered on ADC_SocTrigSrc_EPWM1_ADCSOCA (referring to HAL document for DRVkit - motorware example, just for example).

1. What does ADC_SocNumber_1 signify? Does it mean that the ADCs will start sampling one after another in the order of SocNumber specified? In that case, will we call it a simultaneous sampling of currents?

2. Does it matter if we connect IA, IB, and IC to the same ADC channel or different ADC channels (Channel A and B)? What impact will it have? 

3a.What does ADCINT1 signify? The HAL document suggests using ADCINT1 as the trigger for potentiometer configuration. What will happen if I trigger it on ADC_SocTrigSrc_EPWM1_ADCSOCA?

3b. How does ADC operation change from SocNumber 0 to 7 and from 8 to 15? I guess there is a relation with 3a but I am not able to understand. 

I have read the documents but I am not able to get a hold of all these concepts. Maybe someone can help me understand ADC operation and simultaneous sampling better over here. 

  • 0
    TI__Genius 10845 points
    Hi Rushi,

    You can refer to the ADC chapter in deviceTRM and examples available under C2000Ware to get more details on this.

    Thanks
    Vasudha
  • 0 in reply to Vasudha Bhadoria
    Expert 1225 points
    Hi Vasudha,

    As I have already said, I have gone through the technical reference manual but it became too complex for me to understand. Hence, I have asked my queries on the forum.

    I would be grateful if someone can solve my queries here.
  • 0 in reply to Rushi Jariwala
    Expert 1225 points

    Hi TI,

    I am still searching for an answer to the above question. I would be grateful if someone can spare some time to answer this question.

    Thanks

  • 0
    TI__Genius 10845 points

    Hi Rushi,

    PFB the explanation:

    Rushi Jariwala said:
    1. What does ADC_SocNumber_1 signify? Does it mean that the ADCs will start sampling one after another in the order of SocNumber specified? In that case, will we call it a simultaneous sampling of currents?

    Each SOC defines a configuration for single conversion of a single channel. There are 16 SOCs, SOC0-SOC1 and you can configure any ADC channel & trigger for any of the SOCs. SOCs in default mode are triggered in round robin fashion which means the ADC channels can be sampled in round robin fashion if different SOCs are mapped to different ADC channels. Else multiple SOCs can be mapped to a single channel to achieve oversampling kind of scenario.

    Thanks

    Vasudha

  • 0
    TI__Genius 10845 points

    Rushi Jariwala said:
    2. Does it matter if we connect IA, IB, and IC to the same ADC channel or different ADC channels (Channel A and B)? What impact will it have? 

    Different signals to be sampled need to be connected to different channels.

    Rushi Jariwala said:
    3a.What does ADCINT1 signify? The HAL document suggests using ADCINT1 as the trigger for potentiometer configuration. What will happen if I trigger it on ADC_SocTrigSrc_EPWM1_ADCSOCA?

    The ADC interrupt can be configured to occur at any of SOC's end of conversion. Usually, ADC int is configured to occur at the last SOC EOF and in ISR ADC result can be read. You can refer to ADC examples for more details on this.

    Thanks

    Vasudha