• Locked Locked
  • Replies 4 replies
  • Subscribers 79 subscribers
  • Views 1855 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

About Dual slope calculation is software

Bonnie Baker - WEBENCH Design Center
Expert 3555 points

Hello Bonnie,

 

We are using TI MSP430 for our I/O Module cards and we have a SPI ADC driver for the data acquisition from field transducers.

I wanted to know how to do the Dual slope calculation in ADC code. Can you please suggest me on below

 

Actually, there is already ADC code existing out of which I need to determine if

 

  1. there exists a dual slope calculation
  2. if no , how to add this feature in the driver.

 

We use MSP430 controller for our Analog/Digital I/O modules in CCS.

 

 

Regards

Prasad

  • TI__Expert 3555 points

    Shrisha,

    I am not sure how to do this. I am going to post your question on the TI forum.

     

    Bonnie

  • in reply to Bonnie Baker - WEBENCH Design Center
    Guru 227245 points

    If I knew what 'the dual slope calculation' and 'in ADC code' means...

    ***INSUFFICIENT INPUT ERROR***

  • in reply to Jens-Michael Gross
    Prodigy 10 points

    I wanted to know what should be done in order to force the dual slope calculation for transducers  data acquisition.

    Any special thing in SW ----the calculations in the ADC driver code will ensure that dual slope ADC functionality

     

     

  • in reply to Prasad Ra
    Guru 227245 points

    Looks like we're talking two different languages. :)

    So let me state the basic things.

    The MSP ADCs are either of SAR or Delta-Sigma type.
    There are about 400 different MSPs (there is no 'the MSP') with different hardware features. Some MSPs have an ADC10., some an ADC12, some an SD16 or SD24 or even multiple SD24 modules, some only have a simple comparator and some no ADC at all.

    The SARs (successive approximation registers) ADC10 and ADC12 take a sample of ht einput voltage by a sample&hold stage and convert it into a numerical value relative to the chosen reference voltage. If you program them properly, you'll get a sequence of voltage values. It' sup to you to do with this information whateber you want. Including any fancy filtering. There is no special mode that would "force the dual slope calculation for transducers" (or any other calculation)

    The Delta-Sigmas SD16 and SD24 are second order delta-sigma converters that produce a bitsream whose relation of emitted '1' and '0' bits corresponds to teh input voltage. There is a digital filter after the converter that allows extracting a 16 or 24 bit (or less for smaller OSR settings) result for each 32 to 1024 bits emitted by the converter (the oversampling ratio). There is nothing you can configure except the oversampling ratio OSR (and therefore the sampling time and precision).

    Some few MSPs have an additional hardware state machine that allows some basic operations on the SD24 results in 'hardware'. I have no experience with this but that's all. The rest is up to you and your coding skills.

    You see, I still don't know exactly what you're talking about, but maybe you now also see why .

**Attention** This is a public forum