• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 82 subscribers
  • Views 324 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

F28M35x assign the 2.88MSPS of ADC

hongyue yu
Intellectual 485 points

Other Parts Discussed in Thread: CONTROLSUITE

Hi friends,

I have encountered a problem that how to assign the 2.88MSPS of ADC,there are four analog input that I have assigned.But I am a little confused that how can I assign the 2.88MSPS.For instance,ADCINA1、ADCINA2、ADCINB3、ADCINB4 have been used.I want to assign ADCINA1 1MSPS,ADCINB3 1MSPS,ADCINA2 and ADCINB4 share the others.I don't know what I understand the 2.88MSPS is right or not.Thank you!

Best Regards,

Hongyue

  • 0
    TI__Guru 60865 points

    Hi Hongyue,

    This ADC is configured using SOCs (start of conversions), which are essentially a grouping of a trigger, a channel to convert, a S/H window duration, and a result register where the conversion results go.  The actual sampling rate is for a given channel is determined based on how these SOCs are configured and how the trigger source is configured.  Typically some ePWMs are setup to periodically trigger the ADC. 

     To really understand this, I suggest you give the ADC chapter of the TRM a thorough read (spruh22e - chapter 11) while also running the example ADC projects in ControlSUITE.  You may also want to skim the ePWM chapter of the TRM.  

    Once you have the example projects running and you understand them, you can modify them incrementally to achieve the sampling requirements of your application. 

  • 0 in reply to Devin Cottier
    Intellectual 485 points

    Hi Devin,

    Thank you for your reply! There is still a question to ask for you.I wonder how about the change of between two channels.I don't know whether it can change rapidly between two channels.

    Best Regards,

    Hongyue

  • 0 in reply to hongyue yu
    TI__Guru 60865 points

    Hongyue,

    If you configure two (or more) SOCs to use different channels, and then trigger them, the ADC will automatically select the correct channels and convert them .  This will not add any additional time as compared to sampling the same channel multiple times.

  • 0 in reply to Devin Cottier
    Intellectual 485 points

    Hi Devin,

    Many thanks! For instance,if SOC0(ADCINA0) is double times than SOC1(ADCINA1),I wonder the handling process of ADC(S/H、convert).Maybe the two SOCs will be triggered simultaneously.And if more analog inputs are used,the situation will be more complicated.

    Best Regards,

    Hongyue 

  • 0 in reply to hongyue yu
    TI__Guru 60865 points

    Different SOCs will always convert in a sequence, not in parallel.  

    You can set simultaneous mode, but this requires conversion of a specific channel pair (e.g. A0/B0 or A5/B5), they must use the same acquisition window width, and the same trigger.  This simultaneous sample is configured through one SOC, not two. 

  • 0 in reply to Devin Cottier
    Intellectual 485 points

    Thank you,Devin!

    Best Regards,

    Hongyue