BBB fast pulses counter

[Nicola Cesca]

I want to use BBB as a pulse counter (>50kHz).
Anyone have experience about it?

[Rick Mann]

I haven't done this, but you'd probably need the PRU to do this. There are two Programmable Real-time Units on the BBB SoC; these are smaller 200 MHz processors that you can program directly (no OS), and that run independently of the main processor.

> On Jun 9, 2015, at 04:45 , Nicola Cesca <nicola...@gmail.com> wrote:
>
> I want to use BBB as a pulse counter (>50kHz).
> Anyone have experience about it?
>

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Rick Mann
rm...@latencyzero.com

[Karteek YV]

you have two options
1. Polling from OS using main processor (less accurate and non real time but works fairly good below 1KHz)
2. Polling with one of the PURs (more accurate and real time)

[Karteek YV]

you can modify the example code at https://github.com/derekmolloy/exploringBB/tree/master/chp13/ultrasonic for your purpose
before using do enable PRU by exporting required device tree provided at https://github.com/derekmolloy/exploringBB/tree/master/chp13/overlay to the slots

On Tuesday, 9 June 2015 17:15:19 UTC+5:30, Nicola Cesca wrote:

[TJF]

Hi Nicola

Am Dienstag, 9. Juni 2015 13:45:19 UTC+2 schrieb Nicola Cesca:

I want to use BBB as a pulse counter (>50kHz).
Anyone have experience about it?

I use the QEP modules in the PWMSS subsystems for counting pulses. There's one module in each of the three subsystems, that works @100MHz and can either handle quadrature encode pulses or simply up-count on a single line. See SRM chapter 15.4 for details.

BR

[Rick Mann]

> On Jun 9, 2015, at 13:30 , TJF <jeli.f...@gmail.com> wrote:
>
> I use the QEP modules in the PWMSS subsystems for counting pulses. There's one module in each of the three subsystems, that works @100MHz and can either handle quadrature encode pulses or simply up-count on a single line. See SRM chapter 15.4 for details.

Oh yeah, that's a good way to do it.

--
Rick Mann
rm...@latencyzero.com