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?
You are correct that this application does not need to know the actual real time but only the relative (elapsed) time since the subroutine began. I’m familiar with clock_gettime but didn’t think it could give me subsecond information. I’ll explore it!
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:[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
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.
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.
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.