Re: [beagleboard] Re: Periodic delay reading analog inputs with C, will PRUs solve it and is it worth it?
Hi Mark, let me first point out that this discussion isn't in my mother tongue. Sometimes I read your statements several times still not understanding what exactly you mean. Mark Lazarewicz schrieb am Sonntag, 18. April 2021 um 16:49:22 UTC+2: > who you want to believe Texas Instrumentr or TJF? I believe none of them. The hardware is reality. I make experiments (ask the hardware) to find out what's really correct. There isn't one great TI company. Hardware engineers made a great AM335x CPU design. It's not bug free, but well usable. And software engineers do everything to block the hardware benefits. So the question should be: blinking a led, do you want to follow an CCS example (changing with each new kernel version) or an libpruio example published years before (2014, still working)? Do you want to learn from coders making small examples only, or are you interested in hands-on experience form people who did already fill up the IRam of both PRUSS? You're lucky, I'm waiting for feedback before starting my next project. So I've time to waste of good mojo. -- 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 beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/0646b780-3ac1-41fe-8c7d-3ee2b2156b66n%40googlegroups.com.
Re: [beagleboard] Re: rtcwake support on BeagleBone Blue
Thank you for a comprehensive answer. I will look into external clocks. On Sun, Apr 18, 2021 at 5:05 PM Dennis Lee Bieber wrote: > On Sat, 17 Apr 2021 14:14:03 -0700 (PDT), in > gmane.comp.hardware.beagleboard.user Mykolas Juraitis > wrote: > > >Hello, > > > >I am experimenting with rtcwake on BeagleBone Blue. Running command: > > > > Note that there is no REAL RTC on most BeagleBone variants (I don't > know if the Blue has an add-on RTC). cf: > > https://learn.adafruit.com/adding-a-real-time-clock-to-beaglebone-black/overview > > > >I tried to check time before and after standby by running: > > > >sudo hwclock && date && sudo rtcwake -d /dev/rtc0 -m standby -s 20 && > date > >&& sudo hwclock > >2021-04-17 21:42:40.123908+00:00 > >Sat 17 Apr 2021 09:42:40 PM UTC > >rtcwake: wakeup from "standby" using /dev/rtc0 at Sat Apr 17 21:43:02 2021 > >Sat 17 Apr 2021 09:43:06 PM UTC > >2021-04-17 21:43:07.802256+00:00 > > > >Last 2 time lines are printed after manual wake up by pressing power > >button. They seem to be showing that only twenty some seconds passed but > >actually much more time passed until I pressed power button. Which is > weird > >because if RTC doesn't work then I would expect time to be reset. If it > >does work it should be correct time. > > > > Beaglebones periodically save the system clock value, and use that > to > reload the system clock on startup. The value you are seeing is likely that > of the last time this fake hwclock was written... cf: > https://manpages.debian.org/jessie/fake-hwclock/fake-hwclock.8.en.html > > Also... > > https://unix.stackexchange.com/questions/187261/automatically-update-hwclock-at-boot > https://groups.google.com/g/beagleboard/c/n1noGnM30sQ > > > > -- > Dennis L Bieber > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to a topic in the > Google Groups "BeagleBoard" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/beagleboard/qPoSZk2XStA/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > beagleboard+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/a3mo7gls3hp901pi4r91rfvkkq7q7g2nti%404ax.com > . > -- 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 beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAKVuKxgb%3DQM4ek_D_zwqRzBugNAD3JhS7KYLBO_w5YmvADPhwg%40mail.gmail.com.
[beagleboard] Re: rtcwake support on BeagleBone Blue
On Sat, 17 Apr 2021 14:14:03 -0700 (PDT), in gmane.comp.hardware.beagleboard.user Mykolas Juraitis wrote: >Hello, > >I am experimenting with rtcwake on BeagleBone Blue. Running command: > Note that there is no REAL RTC on most BeagleBone variants (I don't know if the Blue has an add-on RTC). cf: https://learn.adafruit.com/adding-a-real-time-clock-to-beaglebone-black/overview >I tried to check time before and after standby by running: > >sudo hwclock && date && sudo rtcwake -d /dev/rtc0 -m standby -s 20 && date >&& sudo hwclock >2021-04-17 21:42:40.123908+00:00 >Sat 17 Apr 2021 09:42:40 PM UTC >rtcwake: wakeup from "standby" using /dev/rtc0 at Sat Apr 17 21:43:02 2021 >Sat 17 Apr 2021 09:43:06 PM UTC >2021-04-17 21:43:07.802256+00:00 > >Last 2 time lines are printed after manual wake up by pressing power >button. They seem to be showing that only twenty some seconds passed but >actually much more time passed until I pressed power button. Which is weird >because if RTC doesn't work then I would expect time to be reset. If it >does work it should be correct time. > Beaglebones periodically save the system clock value, and use that to reload the system clock on startup. The value you are seeing is likely that of the last time this fake hwclock was written... cf: https://manpages.debian.org/jessie/fake-hwclock/fake-hwclock.8.en.html Also... https://unix.stackexchange.com/questions/187261/automatically-update-hwclock-at-boot https://groups.google.com/g/beagleboard/c/n1noGnM30sQ -- Dennis L Bieber -- 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 beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/a3mo7gls3hp901pi4r91rfvkkq7q7g2nti%404ax.com.
Re: [beagleboard] Re: Periodic delay reading analog inputs with C, will PRUs solve it and is it worth it?
TJF* I Dont* agree and neither do companies that have sold 10k products that sounds finished to me unfortunately CCS doesnt support Basic language so I can see why your worried and I wish you the best of luck getting libpruio inluded in the kernel sincerely. Linux is great I just dont use it for hard realtime I an in line with TI marketing see below link. The reason the PRU is there is to allow linux as a gateway and hard realtime is done on the PRU. The original poster's project IS NOT hard REAL Time perhaps you can help him get his project working on ARM since thats all you understand. * Ensuring real-time predictability* https://www.ti.com/lit/pdf/spry264 The fact that TI also supports QNX , Intergrity and Nucleeus see here https://www.ti.com/tool/TMDSSK3358 shows TI knows what real customers want besides Linux I wont insult you like you attempted to do to me as I consider the source someone who does not develop just pays for solutions you have zero credibility. Anyway my code is up and running and for the group I will offer another path the AM335X has touch screen and onboard FTDI jtag and isntructions for using CCS on it and Beagle Bone Black. Add up the cost of a JTAG and touch screen its actually reasonable its here https://www.ti.com/lit/ug/sprw236b/sprw236b.pdf I repeat again from TI a great company with great engineers read this its actually related to the posters original question unlike this angry uncalled for post . who you want to believe Texas Instrumentr or TJF? BTW Rproc and RPMsg is supported by TI in Linux kernel and TI RTTOS its also documented well not Doxygen comments lifted from code Some real latencies and exact access times in block diagram no snake oil https://www.ti.com/lit/ug/sprw236b/sprw236b.pdf CCS/JTAG is an option not for everyone but recommended for board bring up you know the real work that engineers do. not some bean counter who doesn't actually do the work The user can make his own choices I'm just trying to be helpful Mark On Sunday, April 18, 2021 at 1:09:43 AM UTC-5 TJF wrote: > Hi Mark, > > you're the master of reversed order! You want to code a main loop before > IO is working. You want to CCS/JTAG variables before your first LOC is > running. Did you ever finish a project? > > When a subsystem is off (not clocked) the PRU can still read or write its > registers. Readings are always zero and writings go to Nirvana, no error > message, no exeption. How should a debugger help in this case? > > Mark Lazarewicz schrieb am Sonntag, 18. April 2021 um 03:13:10 UTC+2: > >> Anyway Linux is not required for CCS and its slow and inferior to Windows >> 10 version > > > LINUX is stable and reliable. Anyway, CSS is not required for PRU > development. Since I aim to open up the full PRUSS power (I've payed for), > I continue ignoring all that CSS bloat (!! a linker for a 2k instruction > space !!). > > Regards > -- 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 beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/60fb316a-c523-4d88-a3b1-afc598e8af83n%40googlegroups.com.
Re: [beagleboard] Re: Periodic delay reading analog inputs with C, will PRUs solve it and is it worth it?
Hi Mark, you're the master of reversed order! You want to code a main loop before IO is working. You want to CCS/JTAG variables before your first LOC is running. Did you ever finish a project? When a subsystem is off (not clocked) the PRU can still read or write its registers. Readings are always zero and writings go to Nirvana, no error message, no exeption. How should a debugger help in this case? Mark Lazarewicz schrieb am Sonntag, 18. April 2021 um 03:13:10 UTC+2: > Anyway Linux is not required for CCS and its slow and inferior to Windows > 10 version LINUX is stable and reliable. Anyway, CSS is not required for PRU development. Since I aim to open up the full PRUSS power (I've payed for), I continue ignoring all that CSS bloat (!! a linker for a 2k instruction space !!). Regards -- 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 beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/4caa73f5-e1a9-4342-b0c0-0b4fdf9ef98bn%40googlegroups.com.
