Count external clock pulses with hardware counter on C2000

RLetizia

I would like to count an external pulse stream with an internal hardware counter. The pulse stream clocks the hardware counter; the hardware counter will be interrogated periodically to calculate an input rate.

The pulse stream is connected to pin GPIO24/ECAP1/EQEP2A/SPISIMOB.

The signal is not quadrature so I don’t see how to use the EQEP module.

I’ve also looked at the ECAP documentation and don’t see how it can be configured to just count pulses in a hardware counter.

Given the signal comes in on this pin, any ideas to count the pulses? Either count one edge, or better yet count both edges: pulse high transition= count++, pulse low transition = count++;

Is taking an interrupt on the pulse edge the only method?

Thanks.

over 10 years ago

0 Gautam Iyer over 10 years ago

Guru 192875 points

Hi,

You have 2 options here either use eCAP module or GPIO as input/external interrupt.

I’ve also looked at the ECAP documentation and don’t see how it can be configured to just count pulses in a hardware counter.

This is the best peripheral to do so.

Regards,
Gautam

0 Brett Larimore over 10 years ago in reply to Gautam Iyer

TI__Guru 57255 points

Hi,

The eQEP is actually your best option. Take a look at the eQEP's Pulse/Direction count mode.

Configured in this mode, you should tie some QEP's A input to a square wave signal and then tie QEP's B input to either logic-high or logic-low. The QEP will the automatically count the number of pulses received.

Hopefully this helps!

Thank you,
Brett

0 RLetizia over 10 years ago in reply to Brett Larimore

Intellectual 990 points

Thanks Brett, Gautam.

0 Gautam Iyer over 10 years ago in reply to RLetizia

Guru 192875 points

You're Welcome!

Goodluck and Regards,
Gautam

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Count external clock pulses with hardware counter on C2000