[beagleboard] Re: Time synchronization of hardware clock and PRU?

Kernel module timers are in the eCAP modules in the PWMSS subsystems. Three modules are present, but only two are wired to the big headers, the third is at JT or SDcard-slot (32 bit counters at 100 MHz --> maximal toggling time stamp = 42,9s). Additional the TIMER[4-7] subsystems provide that

[beagleboard] Re: Time synchronization of hardware clock and PRU?

Thank you for explanation. I have discussed this with my mentor - for now, we will focus on accuracy and drift of the processor clock. We found out Beaglebone Black has support for high resolution timers within kernel modules - the kind that support nanosecond timestamping with ktime_get and

[beagleboard] Re: Time synchronization of hardware clock and PRU?

On Fri, 28 Feb 2020 01:35:54 -0800 (PST), in gmane.comp.hardware.beagleboard.user Jaka Koren wrote: > >There are obviously obstacles, the first one with Linux not being a real >time operating system. One part of my research is measuring the delay >caused by task scheduling, but for now I want

[beagleboard] Re: Time synchronization of hardware clock and PRU?

Your target seems to be possible. The PRU clock is very stable. Start with example code at pruss_toggle . Adapt the pinmuxing and the PRU firmware: 1. PRU generates your desired 1 Hz pulse

Re: [beagleboard] Re: Time synchronization of hardware clock and PRU?

Can you explain this? then synchronizing the hardware clock and PRU to the obtained timestamp Typically you synchronize a software timer which is  based off the  processor clock and adjust it for drift if your goal is to have two board's running on exactly same Time  to a sub microsecond

Re: [beagleboard] Re: Time synchronization of hardware clock and PRU?

We have been using a Beaglebone Black for a while now using the PRU(s) for time sensitive experiments. In our estimate the PRU has shown a very stable clock, running at 200MHz with tight control. The clock does run off a very stable TCXO and the two PRUs are synchronized to within mHz of offset

[beagleboard] Re: Time synchronization of hardware clock and PRU?

On Fri, 28 Feb 2020 01:35:54 -0800 (PST), in gmane.comp.hardware.beagleboard.user Jaka Koren wrote: >-Is using a PRU even suitable for this kind of experiment? I am aiming for >sub-microsecond accuracy. >-My task for example would require obtaining global time via selected >protocol, then