TMS570LS3137: ADC Can be Used As CCP For TMS570LS3137

user6220345

Part Number: TMS570LS3137

Hello,

As googling on the net, i have encounterd capture and compare can be done via HET. My question is: is it possible to do Capture and compare with ADC.

Thanks.

over 5 years ago

0 QJ Wang over 5 years ago

TI__Guru**** 196736 points

Hello,

NHET is to capture the input digital signal: edge (rising or falling), pulse high, pulse low, period.

ADC is used to sample the analog input signal. Yes, you can use ADC to continuously sample a digital input signal, calculate the pulse high or low and period. But this method is not accurate, it accuracy depends on the ADC sampling frequency and your detection algorithm. This method takes most of the CPU bandwidth.

0 Sunil Oak over 5 years ago in reply to QJ Wang

TI__Mastermind 49120 points

The ADC supports a magnitude threshold compare interrupt mechanism. You can use this to set up a compare threshold and a comparison condition for a channel that is continuously converted. An interrupt is generated to the CPU when the defined comparison condition is true.

This allows you to implement a compare window without using any CPU bandwidth.

0 user6220345 over 5 years ago in reply to QJ Wang

Intellectual 440 points

How can we measure the frequency with timer (HET).

0 QJ Wang over 5 years ago in reply to user6220345

TI__Guru**** 196736 points

If your input is a PWM signal, the instruction PCNT captures the period between 2 rising edges, or two falling edges.

Please refer to the PCNT in TRM

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TMS570LS3137: ADC Can be Used As CCP For TMS570LS3137