RM57L843: eCAP module limitation

Shantanu Salunkhe

Part Number: RM57L843
Other Parts Discussed in Thread: HALCOGEN

Hello,

I want to know about the eCAP module limitation in terms of frequency/period. I have a application in which I need to capture and measure period of a signal which is around 1Mhz-2Mhz in frequency.

Will eCAP module be able to capture and measure its period or is there any other module by which I can do this.

Thanks & Regards.

over 4 years ago

0 QJ Wang over 4 years ago

TI__Guru**** 197336 points

Hello Shantanu,

The maximum frequency of the input signal is the half of VCLK3. For measuring the period of a higher input signal, you can use the event prescaler to prescale the input signal.

0 Shantanu Salunkhe over 4 years ago in reply to QJ Wang

Intellectual 440 points

Thanks for your reply,

I want to ask can N2HET module measure this high frequency signal, since in document spna225 it has a timing limitation of 1.422us.

link to document: www.ti.com/.../spna225.pdf

0 QJ Wang over 4 years ago in reply to Shantanu Salunkhe

TI__Guru**** 197336 points

Hello,

It depends on how many NHET instructions are used in your NHET code. If the lr is 128, the LRP=lr*(1/VCLK) which may be bigger than 1us. If lr=8 (less than 8 instructions in your code), LRP=8*1/VCLK =8/75(MHz) = 112ns

0 Shantanu Salunkhe over 4 years ago in reply to QJ Wang

Intellectual 440 points

Hello,

Does this means I need to code N2HET in assembly language to get the best performance out of it.

If yes how can I do it, since I'm not familiar with assembly coding. Or it can done with HalCoGen also.?

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RM57L843: eCAP module limitation