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RTOS/MSP432E401Y: Setting ADC Sampling Duration for Single Sequencer Channel

Sven Probst
Expert 1630 points
Part Number: MSP432E401Y


Tool/software: TI-RTOS

Dear Experts,

how can I set the sampling duration for a single sequencer channel, but not all in the ADCBuf TI Driver?

I want to use the internal temperature sensor. According to SLAU723, p. 759 "the sample and hold width should be at least 16
ADC clocks (TSHn = 0x4)." The sequencer allow different settings for each sequencer channel entry, but the TI driver supports a global setting only (as far as I understand).

A longer sample time for all channels of both ADCs is not acceptable because we use 18 channels.

It would already help me if I could restrict the longer sample time to one ADC or sequencer only. Is it an option to change the adcBufParams.custom field before calling the ADCBuf_open function to affect only one ADC?

  • 0
    TI__Guru**** 244400 points
    Hello Sven,

    No, it is not possible right now to set one channel in a sequencer with a specific Sample and Hold value. However it is possible to do it across two ADCs. One ADC will be exclusively used by the temperature sensor and you would need to add the following when calling ADC_open

    struct ADCBufMSP432E4_ParamsExtension adcBufParamsEx;
    adcBufParamsEx.samplingDuration = ADCBufMSP432E4_SamplingDuration_PULSE_WIDTH_16;
    adcBufParams.custom = &adcBufParamsEx;

    The 2nd ADC instance will be used for other channels that can work of the same Sample and Hold.

    I have asked for an enhancement for the same so that it can be configured per channel per sequencer as given in the TRM.

    If this is not acceptable then only work around I would suggest is to update the specific register using direct register access to update the sample and hold setting for the temp sensor channel in the specific sequencer.

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