Walter:
  It's good to hear you have the PRUs working.  I still think if all you 
need is millisecond timing the PRUs are over kill.

In C you can use *usleep()* and pass it the number of microseconds you want 
to pause.

--Mark
On Thursday, February 18, 2021 at 10:00:10 AM UTC-5 
[email protected] wrote:

> I've gone through the cookbook and it's very helpful. 
>
> I'm still fuzzy on how to do what I need to do.  
>
> My main code for controlling the valves, getting user input, etc. is in 
> C.  
>
> I need to call a procedure in C that reads sensors.  I will pass this 
> procedure the number of milliseconds it should read the sensors and then 
> return to the main program and turn the valves off.   The number of 
> milliseconds can, and will likely, change depending on what we are 
> processing with these valves.   I get that input at the start of the main 
> program.    
>
> My thought is that in the procedure that reads the sensors, it will grab a 
> start time (doesn't have to be actual time) value from the PRU, read the 
> sensors, and loop until the current time-start time equals the amount of 
> time it should read the sensors.  Then it will return to the main program.
>
> I just don't know how to read the PRU's clock to get the time values.   I 
> don't think I saw an example in the cookbook for 'branching' out from a 
> main program to use the PRUs for this type of processing.  Just point me in 
> the right direction, please.
>
> Walter
>
>
> On Thursday, February 18, 2021 at 9:27:34 AM UTC-5 Walter Cromer wrote:
>
>> Mark ,
>>
>> It is working with the updated OS.  Thanks so much!   
>>
>> Now I will explore how to get the simple timing that I need using the PRU.
>>
>> On Thursday, February 18, 2021 at 8:54:10 AM UTC-5 Walter Cromer wrote:
>>
>>> Mark, 
>>>
>>> With the current OS there isn't a /dev/remoteproc even.   
>>>
>>> I'm going to try the updated OS build this morning.  
>>>
>>> Walter
>>>
>>> On Wednesday, February 17, 2021 at 5:34:37 PM UTC-5 Mark A. Yoder wrote:
>>>
>>>> I fired up the Beagle at home it the PRU works out of the box.
>>>>
>>>> What do you get running
>>>> *ls /dev/remoteproc*
>>>>
>>>> I get:
>>>> *ls -ls /dev/remoteproc*
>>>> total 0
>>>> 0 lrwxrwxrwx 1 root root 33 Feb 17 17:26 pruss-core0 -> 
>>>> /sys/class/remoteproc/remoteproc1
>>>> 0 lrwxrwxrwx 1 root root 33 Feb 17 17:26 pruss-core1 -> 
>>>> /sys/class/remoteproc/remoteproc2
>>>>
>>>> If you are missing pruss-core0 and pruss-core1 you could try adding the 
>>>> links by hand and see what happens.
>>>>
>>>> *cd /dev/remoteproc*
>>>>
>>>> *sudo ln -s /sys/class/remoteproc/remoteproc1 pruss-core0*
>>>> *sudo ln -s /sys/class/remoteproc/remoteproc2 pruss-core1*
>>>> On Wednesday, February 17, 2021 at 3:56:21 PM UTC-5 
>>>> [email protected] wrote:
>>>>
>>>>> I'll get this one onto an SD card and give it a try.   If I can just 
>>>>> get this configured I think I can make quick work of this problem!  
>>>>>
>>>>> On Wednesday, February 17, 2021 at 3:47:04 PM UTC-5 Mark A. Yoder 
>>>>> wrote:
>>>>>
>>>>>> Good point, it should work....  I'm running a newer test image[1], 
>>>>>> but I took my Beagle home so I can't do a quick check on it until later.
>>>>>>
>>>>>>
>>>>>> --Mark
>>>>>> [1]
>>>>>> https://rcn-ee.com/rootfs/bb.org/testing/2021-02-15/buster-iot/bone-debian-10.8-iot-armhf-2021-02-15-4gb.img.xz
>>>>>>  
>>>>>>
>>>>>> On Wednesday, February 17, 2021 at 2:46:35 PM UTC-5 
>>>>>> [email protected] wrote:
>>>>>>
>>>>>>> I asked because the ones on the page @ the link are older than the 
>>>>>>> one I have installed.
>>>>>>>
>>>>>>>
>>>>>>> On Wednesday, February 17, 2021 at 2:30:58 PM UTC-5 Mark A. Yoder 
>>>>>>> wrote:
>>>>>>>
>>>>>>>> On newer versions of the SD card image /var/lib/cloud9 is a git 
>>>>>>>> repo which you can do a git pull to update.  Your version is too old.
>>>>>>>>
>>>>>>>> Follow the instructions at: 
>>>>>>>> https://markayoder.github.io/PRUCookbook/02start/start.html#_installing_the_latest_os_on_your_bone
>>>>>>>>  
>>>>>>>> to download and install an updated version of the SD card image.
>>>>>>>>
>>>>>>>> --Mark
>>>>>>>>
>>>>>>>> On Wednesday, February 17, 2021 at 2:25:40 PM UTC-5 
>>>>>>>> [email protected] wrote:
>>>>>>>>
>>>>>>>>> Mark, 
>>>>>>>>>
>>>>>>>>> git pull on /var/lib/cloud9 fails with 'fatal: Not a git 
>>>>>>>>> repository (or any of the parent directories): .git 
>>>>>>>>>
>>>>>>>>> I'm such a neophyte on git.  What do I need to do?
>>>>>>>>>
>>>>>>>>> And, what do you mean by updating to a new version of the SD card? 
>>>>>>>>> The OS is booting from the SD card and the version.sh information 
>>>>>>>>> posted 
>>>>>>>>> earlier is based on that.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Wednesday, February 17, 2021 at 2:02:55 PM UTC-5 Mark A. Yoder 
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>> I suggest updating to a new version of the SD card.  It looks 
>>>>>>>>>> like the PRUs are getting started at boot time, but the path isn't 
>>>>>>>>>> setup 
>>>>>>>>>> right. I think we setup some links so the path* 
>>>>>>>>>> /dev/remoteproc/pruss-core0/state  
>>>>>>>>>> *points to the right place.
>>>>>>>>>>
>>>>>>>>>> You could also try:
>>>>>>>>>> *cd */var/lib/cloud9
>>>>>>>>>> *git* pull
>>>>>>>>>> to update cloud9 folders.
>>>>>>>>>>
>>>>>>>>>> --Mark
>>>>>>>>>>
>>>>>>>>>> On Wednesday, February 17, 2021 at 1:53:35 PM UTC-5 
>>>>>>>>>> [email protected] wrote:
>>>>>>>>>>
>>>>>>>>>>> Mark, 
>>>>>>>>>>>
>>>>>>>>>>> I got the latest PRUCookbook downloaded and when trying to make 
>>>>>>>>>>> the hello.pru0.c program in 1.6, I got this error.  
>>>>>>>>>>>
>>>>>>>>>>> *debian@beaglebone:/var/lib/cloud9/PRUCookbook/docs/02start/code$ 
>>>>>>>>>>> make TARGET=hello.pru0*
>>>>>>>>>>> */var/lib/cloud9/common/Makefile:29: 
>>>>>>>>>>> MODEL=TI_AM335x_BeagleBone_Black,TARGET=hello.pru0*
>>>>>>>>>>> *-    Stopping PRU 0*
>>>>>>>>>>> */bin/sh: 1: cannot create /dev/remoteproc/pruss-core0/state: 
>>>>>>>>>>> Directory nonexistent*
>>>>>>>>>>> *Cannot stop 0*
>>>>>>>>>>> *CC      hello.pru0.c*
>>>>>>>>>>> *"/var/lib/cloud9/common/prugpio.h", line 53: warning #1181-D: 
>>>>>>>>>>> #warning directive: "Found am335x"*
>>>>>>>>>>> *LD      /tmp/cloud9-examples/hello.pru0.o*
>>>>>>>>>>> *-       copying firmware file 
>>>>>>>>>>> /tmp/cloud9-examples/hello.pru0.out to /lib/firmware/am335x-pru0-fw*
>>>>>>>>>>> *cp: cannot create regular file '/lib/firmware/am335x-pru0-fw': 
>>>>>>>>>>> Permission denied*
>>>>>>>>>>> */var/lib/cloud9/common/Makefile:180: recipe for target 
>>>>>>>>>>> 'install' failed*
>>>>>>>>>>> *make: *** [install] Error 1*
>>>>>>>>>>> *rm /tmp/cloud9-examples/hello.pru0.o*
>>>>>>>>>>>
>>>>>>>>>>>  Initially, I did not have a folder called 
>>>>>>>>>>> /var/lib/cloud9/common.  To remedy this I copied the contents of 
>>>>>>>>>>> /var/lib/cloud9/PRUCookbook/docs/common to /var/lib/cloud9/common.  
>>>>>>>>>>> Maybe 
>>>>>>>>>>> this created a problem?Nevertheless,  I found some other 
>>>>>>>>>>> discussions that 
>>>>>>>>>>> suggested updating the scripts and kernels from 
>>>>>>>>>>> beagleboard.org/upgrade which I did.  I am now running...
>>>>>>>>>>>
>>>>>>>>>>> Linux beaglebone 4.14.108-ti-r137 #1stretch SMP PREEMPT Tue Aug 
>>>>>>>>>>> 25 01:48:39 UTC 2020 armv7l GNU/Linux
>>>>>>>>>>>
>>>>>>>>>>> And the output of version.sh is 
>>>>>>>>>>>
>>>>>>>>>>> *debian@beaglebone:/$ sudo opt/scripts/tools/version.sh*
>>>>>>>>>>> *[sudo] password for debian:*
>>>>>>>>>>> *git:/opt/scripts/:[e4e4854ef8ff9ada5c85553376043ee7679167ca]*
>>>>>>>>>>> *eeprom:[A335BNLT00C04417BBBK1847]*
>>>>>>>>>>> *model:[TI_AM335x_BeagleBone_Black]*
>>>>>>>>>>> *dogtag:[BeagleBoard.org Debian Image 2018-10-07]*
>>>>>>>>>>> *bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot SPL 
>>>>>>>>>>> 2018.09-00002-g0b54a51eee (Sep 10 2018 - 19:41:39 
>>>>>>>>>>> -0500)]:[location: dd 
>>>>>>>>>>> MBR]*
>>>>>>>>>>> *bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot 
>>>>>>>>>>> 2018.09-00002-g0b54a51eee]:[location: dd MBR]*
>>>>>>>>>>> *bootloader:[eMMC-(default)]:[/dev/mmcblk1]:[U-Boot SPL 
>>>>>>>>>>> 2018.03-00002-gac9cce7c6a (Apr 05 2018 - 13:07:46 
>>>>>>>>>>> -0500)]:[location: dd 
>>>>>>>>>>> MBR]*
>>>>>>>>>>> *bootloader:[eMMC-(default)]:[/dev/mmcblk1]:[U-Boot 
>>>>>>>>>>> 2018.03-00002-gac9cce7c6a]:[location: dd MBR]*
>>>>>>>>>>> *UBOOT: Booted Device-Tree:[am335x-boneblack-uboot-univ.dts]*
>>>>>>>>>>> *kernel:[4.14.108-ti-r137]*
>>>>>>>>>>> *nodejs:[v6.14.4]*
>>>>>>>>>>> */boot/uEnv.txt Settings:*
>>>>>>>>>>> *uboot_overlay_options:[enable_uboot_overlays=1]*
>>>>>>>>>>>
>>>>>>>>>>> *uboot_overlay_options:[uboot_overlay_addr0=/lib/firmware/BB-W1-P9.12-00A0.dtbo]*
>>>>>>>>>>> *uboot_overlay_options:[disable_uboot_overlay_video=1]*
>>>>>>>>>>>
>>>>>>>>>>> *uboot_overlay_options:[uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-14-TI-00A0.dtbo]*
>>>>>>>>>>> *uboot_overlay_options:[enable_uboot_cape_universal=1]*
>>>>>>>>>>> *pkg check: to individually upgrade run: [sudo apt install 
>>>>>>>>>>> --only-upgrade <pkg>]*
>>>>>>>>>>>
>>>>>>>>>>> *pkg:[bb-cape-overlays]:[4.4.20180928.0-0rcnee0~stretch+20180928]*
>>>>>>>>>>> *pkg:[bb-customizations]:[1.20180815-0rcnee0~stretch+20180815]*
>>>>>>>>>>> *WARNING:pkg:[bb-usb-gadgets]:[NOT_INSTALLED]*
>>>>>>>>>>> *pkg:[bb-wl18xx-firmware]:[1.20180517-0rcnee0~stretch+20180517]*
>>>>>>>>>>> *pkg:[kmod]:[23-2rcnee1~stretch+20171005]*
>>>>>>>>>>>
>>>>>>>>>>> *pkg:[librobotcontrol]:[1.0.3-git20181005.0-0rcnee0~stretch+20181005]*
>>>>>>>>>>>
>>>>>>>>>>> *pkg:[firmware-ti-connectivity]:[20170823-1rcnee1~stretch+20180328]*
>>>>>>>>>>> *groups:[debian : debian adm kmem dialout cdrom floppy audio dip 
>>>>>>>>>>> video plugdev users systemd-journal i2c bluetooth netdev cloud9ide 
>>>>>>>>>>> gpio pwm 
>>>>>>>>>>> eqep admin spi tisdk weston-launch xenomai]*
>>>>>>>>>>> *cmdline:[console=ttyO0,115200n8 
>>>>>>>>>>> bone_capemgr.uboot_capemgr_enabled=1 root=/dev/mmcblk0p1 ro 
>>>>>>>>>>> rootfstype=ext4 
>>>>>>>>>>> rootwait coherent_pool=1M net.ifnames=0 quiet]*
>>>>>>>>>>> *dmesg | grep remote*
>>>>>>>>>>> *[    1.147260] remoteproc remoteproc0: wkup_m3 is available*
>>>>>>>>>>> *[    1.231303] remoteproc remoteproc0: powering up wkup_m3*
>>>>>>>>>>> *[    1.231426] remoteproc remoteproc0: Booting fw image 
>>>>>>>>>>> am335x-pm-firmware.elf, size 217168*
>>>>>>>>>>> *[    1.233981] remoteproc remoteproc0: remote processor wkup_m3 
>>>>>>>>>>> is now up*
>>>>>>>>>>> *[  108.634522] remoteproc remoteproc1: 4a334000.pru is 
>>>>>>>>>>> available*
>>>>>>>>>>> *[  108.656634] remoteproc remoteproc2: 4a338000.pru is 
>>>>>>>>>>> available*
>>>>>>>>>>> *dmesg | grep pru*
>>>>>>>>>>> *[  108.019424] pruss 4a300000.pruss: creating PRU cores and 
>>>>>>>>>>> other child platform devices*
>>>>>>>>>>> *[  108.634522] remoteproc remoteproc1: 4a334000.pru is 
>>>>>>>>>>> available*
>>>>>>>>>>> *[  108.634642] pru-rproc 4a334000.pru: PRU rproc node 
>>>>>>>>>>> /ocp/pruss_soc_bus@4a326004/pruss@0/pru@34000 probed successfully*
>>>>>>>>>>> *[  108.656634] remoteproc remoteproc2: 4a338000.pru is 
>>>>>>>>>>> available*
>>>>>>>>>>> *[  108.656808] pru-rproc 4a338000.pru: PRU rproc node 
>>>>>>>>>>> /ocp/pruss_soc_bus@4a326004/pruss@0/pru@38000 probed successfully*
>>>>>>>>>>> *dmesg | grep pinctrl-single*
>>>>>>>>>>> *[    0.783913] pinctrl-single 44e10800.pinmux: 142 pins at pa 
>>>>>>>>>>> f9e10800 size 568*
>>>>>>>>>>> *dmesg | grep gpio-of-helper*
>>>>>>>>>>> *[    0.796624] gpio-of-helper ocp:cape-universal: ready*
>>>>>>>>>>> *lsusb*
>>>>>>>>>>> *Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub*
>>>>>>>>>>> *END*
>>>>>>>>>>>
>>>>>>>>>>> Any ideas?
>>>>>>>>>>>
>>>>>>>>>>> On Wednesday, February 17, 2021 at 10:10:53 AM UTC-5 Mark A. 
>>>>>>>>>>> Yoder wrote:
>>>>>>>>>>>
>>>>>>>>>>>> The PRUs can give you 10's of ns timing, which is more than 
>>>>>>>>>>>> good enough for milliseconds, but might be over kill.
>>>>>>>>>>>>
>>>>>>>>>>>> I'd think using C on the ARM processor should be fast enough.  
>>>>>>>>>>>> I'd use gpiod[1].
>>>>>>>>>>>>
>>>>>>>>>>>> If you really want the ns timing of the PRUs, check out the PRU 
>>>>>>>>>>>> Cookbook[2]
>>>>>>>>>>>>
>>>>>>>>>>>> --Mark
>>>>>>>>>>>>
>>>>>>>>>>>> [1] https://github.com/starnight/libgpiod-example
>>>>>>>>>>>> [2] https://github.com/MarkAYoder/PRUCookbook
>>>>>>>>>>>>
>>>>>>>>>>>> On Tuesday, February 16, 2021 at 10:51:11 AM UTC-5 
>>>>>>>>>>>> [email protected] wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>> Depending on how precise you need to be, I would go for the 
>>>>>>>>>>>>> PRU-ICSS. They can control the GPIOs pretty easily. 
>>>>>>>>>>>>>
>>>>>>>>>>>>> Le mardi 16 février 2021 à 10:03:47 UTC-5, 
>>>>>>>>>>>>> [email protected] a écrit :
>>>>>>>>>>>>>
>>>>>>>>>>>>>> I have a BBB Wireless running Linux beaglebone 
>>>>>>>>>>>>>> 4.14.108-ti-r106 #1 SMP PREEMPT Fri May 24 22:12:34 UTC 2019 
>>>>>>>>>>>>>> armv7l 
>>>>>>>>>>>>>> GNU/Linux
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I am writing in C.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I turn a valve on and then need to read some sensors for N 
>>>>>>>>>>>>>> milliseconds and then turn the valve off.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> What's the best way to read milliseconds on the BBBw?  I 
>>>>>>>>>>>>>> don't have a RTC on this particular unit but could add one using 
>>>>>>>>>>>>>> I2C.  I 
>>>>>>>>>>>>>> have an Adafruit 4282 with a DS3231 RTC on it on another BBBw 
>>>>>>>>>>>>>> that I could 
>>>>>>>>>>>>>> use temporarily to prove it works.  What other options are 
>>>>>>>>>>>>>> available?
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>

-- 
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