Thanks Charles, that's very helpful. I didn't know about the IEP timer. TRM section 4.4.3.1 says I can hook up the IEP clock source to either iep_clk or ocp_clk. Which one of those clocks drives the PRU cycle counter?
Thanks, Justin On Thu, Dec 22, 2016 at 1:43 PM, Charles Steinkuehler < [email protected]> wrote: > On 12/22/2016 10:45 AM, Justin Pearson wrote: > > I have the same question. > > > > I'm using the PRU's 200 MHz cycle counter to timestamp sensor > measurements. At > > 200 MHz, this 32-bit counter overflows in 20 seconds. I would like to > notify a C > > program running on the 1GHz host ARM processor as soon as it overflows. > > > > *Is it possible to configure the PRU cycle counter to trigger an > interrupt in > > the host ARM when it overflows?* > > Do you mean the Cycle register (offset 0x0C in the PRU_ICSS_PRU_CTRL > register bank)? If so, this counter doesn't even wrap around (it > automatically stops when it hits 0xFFFFFFFF) much less generate an > interrupt. > > > I know how to write PRU code to make the PRU trigger an interrupt in the > host, > > but that's not quite what I want, since my PRU will be busy doing other > things. > > I would like the cycle counter to trigger an interrupt automatically, > without > > the PRU having to check if it has overflowed. > > Try using the IEP timer. It will wrap automatically, and you can even > setup a configurable period by using compare register zero and setting > the CMP0_RST_CNT_EN bit. You can also route an IEP timer event > (pr1_iep_tim_cap_cmp_pend) to the ARM core to generate an interrupt. > > -- > Charles Steinkuehler > [email protected] > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/beagleboard/3e1b910f-6ec3-06d1-ab1c-fd10dd3c7856%40steinkuehler.net. > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CABCHBhL4oQa2sfFb8aVtio_1UEbSDZM1tt0S%3DtB6PvhBXGwYOw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
