First off, Thanks Robert for all your help. Looks like we are up and running!
Next, I wanted to post a few notes in case others run into the issues that I had. 1) From a clean install, apt-get update then apt-get upgrade 2) git clone https://github.com/beagleboard/bb.org-overlays.git 3) cd bb.org-overlays/src/arm 4) Create your *.dbs file in this directory (above in thread) 5) back up two levels to /bb.org-overlays/ and issue ./install.sh 6) edit /boot/uEnv.txt and add: uboot_overlay_addr0=/lib/firmware/DD-GPS-00A0.dtbo 7) reboot 8) Here is some short python code to check your NMEA stream: import serial import Adafruit_BBIO.UART as UART GPS = serial.Serial('/dev/ttyS1', 9600) while(1): while GPS.inWaiting()==0: pass NMEA=GPS.readline() print NMEA If all is well, you will see a stream of NMEA data coming across. 9) Run pps-test /dev/pps0 to confirm you have a good pps signal 10) install gpsd from apt-get 11) gpsd -D 5 -n -N /dev/ttyS1 /dev/pps0 12) then run cgps. You should see a valid fix and also in the raw data at the bottom, several lines about pps. 13) install chrony from apt-get 14) edit config: # change the clock slower for less jitter minsamples 10 # get NMEA data from gpsd over shared memory refclock SHM 0 offset 0.395 delay 0.2 refid NMEA noselect # get PPS data from pps-gpio, summarize every 16 seconds, prefer it #refclock PPS /dev/pps0 refid PPS poll 4 prefer refclock PPS /dev/pps0 lock NMEA keyfile /etc/chrony/chrony.keys commandkey 1 driftfile /var/lib/chrony/chrony.drift log tracking measurements statistics logdir /var/log/chrony maxupdateskew 100.0 dumponexit dumpdir /var/lib/chrony # if local stratum is configured and there's a local clock issue, the PPS changes stratum to match this stratum #local stratum 10 allow logchange 0.5 rtconutc # change this to the proper country code #pool us.pool.ntp.org iburst offline Make sure you start gpsd before chronyd. Then run chronyc sources and you should be good to go! Thanks again for all the help! On Thursday, August 30, 2018 at 1:45:11 PM UTC-5, Thomas wrote: > > Robert, > I can't thank you enough for helping me through this. There is very > little information available online regarding this procedure with this > kernel version... > > First, I made the edit that you recommended.. Now, the BBB reboots and I > can see NEMA data coming from the GPS chip. However, when I run PPSTEST > on /dev/pps0, I get the following: > > trying PPS source "/dev/pps0" > found PPS source "/dev/pps0" > ok, found 1 source(s), now start fetching data... > time_pps_fetch() error -1 (Connection timed out) > time_pps_fetch() error -1 (Connection timed out) > time_pps_fetch() error -1 (Connection timed out) > ^C > > > I just measured the P9_12 pin, and I see 2.2v and a 100ms pulse width > square wave coming from the Adafruit GPS receiver. Any other thoughts as > to what might be causing the timeout? > > > > > ---- On Thu, 30 Aug 2018 10:28:46 -0500 Robert Nelson < > [email protected]> wrote ---- > > On Thu, Aug 30, 2018 at 10:18 AM Thomas <[email protected]> > wrote: > > > > > > I have re-imaged my BBB and made the correction to the typo in my > overlay file. However, it appears as if I am having the same issue. When > I install the overlay in the uEnv.txt file and reboot, I am never able to > ssh back into the BBB. > > > > > > My file is below for your review. I can't seem to find any problems > with it, and seem to be stuck again. Do you have any recommendations on > how to proceed? > > > > Your very close, just change one "4" to a "1".. ;) > > > > > > > > > > fragment@1 { > > > target = <&am33xx_pinmux>; > > > __overlay__ { > > > bb_uart4_pins: pinmux_bb_uart1_pins { > > > > These don't match.. > > > > > pinctrl-0 = <&bb_uart1_pins>; > > > > just change: > > > > bb_uart1_pins: pinmux_bb_uart1_pins { > > > > Then it loads correctly.. > > > > uboot_overlays: [fdt_buffer=0x60000] ... > > uboot_overlays: loading /lib/firmware/CLOCK.dtbo ... > > 1607 bytes read in 377 ms (3.9 KiB/s) > > uboot_overlays: loading /lib/firmware/BB-BONE-eMMC1-01-00A0.dtbo ... > > 1440 bytes read in 272 ms (4.9 KiB/s) > > uboot_overlays: loading /lib/firmware/BB-HDMI-TDA998x-00A0.dtbo ... > > 5127 bytes read in 149 ms (33.2 KiB/s) > > uboot_overlays: loading /lib/firmware/BB-ADC-00A0.dtbo ... > > 711 bytes read in 77 ms (8.8 KiB/s) > > uboot_overlays: loading > /lib/firmware/AM335X-PRU-RPROC-4-14-TI-00A0.dtbo ... > > 3513 bytes read in 459 ms (6.8 KiB/s) > > > > debian@beaglebone:~$ dmesg | grep pps > > [ 0.617569] pps_core: LinuxPPS API ver. 1 registered > > [ 0.617576] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 > > Rodolfo Giometti <[email protected]> > > [ 40.470657] pps pps0: new PPS source gps_pps.-1 > > [ 40.470808] pps pps0: Registered IRQ 115 as PPS source > > > > > > debian@beaglebone:~$ ls /dev/pps0 > > /dev/pps0 > > debian@beaglebone:~$ sudo ppstest /dev/pps0 > > trying PPS source "/dev/pps0" > > found PPS source "/dev/pps0" > > ok, found 1 source(s), now start fetching data... > > time_pps_fetch() error -1 (Connection timed out) > > ^C > > > > (i don't have anything wired, so it'll time out) > > > > Regards, > > > > -- > > Robert Nelson > > https://rcn-ee.com/ > > > > > DISCLAIMER: > This e-mail and any attachment(s) sent with it are intended exclusively > for the addressee(s), and may not be used by, opened by, passed on to, or > made available for use to, any person other than the addressee(s). 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