Hello,
Yes to determine the 66.6Mhz I have use the following code :
PRU_GPIO_TOGGLE:
SET PIN //pin high 1
CLR PIN // pin low 2
QBA PRU_GPIO_TOGGLE // jump -2 3
For the 55Mhz I have use this one :
PRU_GPIO_TOGGLE:
SET PIN //pin high
1
XOR r0,r0,0 // like a nope doing nothing interesting 2
CLR PIN // pin low
3
QBA PRU_GPIO_TOGGLE // jump 4
And then I just have to scope it.
Thanks for the information.
Just in case have you got some information about the maximum frequency that
I can reach to read a PIN value (GPIO PIN and PRU dedicated PIN) ?
Regards
Vincent
Le mercredi 4 mai 2016 14:23:38 UTC+2, Dennis Lee Bieber a écrit :
>
> On Wed, 4 May 2016 02:47:43 -0700 (PDT), Le Costaouec Vincent
> <[email protected] <javascript:>> declaimed the
> following:
>
> >Hello,
> >
> >I'm using the PRU, and I have found out that the maximum frequency for a
> >PRU clock is 66 Mhz (or 50Mhz if the duty cycle is at 50%).
> >In the PRU TRM, the data sheet told us that the clock of the PRU is at
> >200MHz.
> >
>
> And how did you determine that 66MHz? By scoping a square-wave
> output
> pin toggle? Off-hand you'd need three instruction cycles for that.
>
> pin high 1
> pin low 2
> jump -2 3 (<G> or is that -3 if the PC has
> incremented already)
>
> 200MHz / 3cycles => 66.67MHz
>
> 50MHz would result from putting a NOP at "1.5" to get the 50% duty
> cycle.
>
> The instruction clock is running 200MHz, it isn't a promise of the
> fastest software output clock you can write using the PRU.
> --
> Wulfraed Dennis Lee Bieber AF6VN
> [email protected] <javascript:> HTTP://wlfraed.home.netcom.com/
>
>
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