Just as a side note here, I am on /dev/ttyAMA1 because the Raspberry Pi 4 has additional UARTs that can be configured with other device tree overlays.
> On Sep 15, 2020, at 9:02 PM, Hal Murray <hmur...@megapathdsl.net> wrote: > >> But then I do not use something like a Rasberry. > > On a Pi, the built in serial port is /dev/ttyAMA0 > It doesn't have any pins for the modem control signals. > At least with the typical setup. > > On a Pi and similar SoC chips, there are not enough pins for all the > potential > uses. There is a layer of muxing between the pins and the built in I/O > devices. The normal setup assigns lots of pins to GPIO. With some work, you > could probably activate the modem control signals. I think device-tree is > the > buzz word. > > On a Pi, the usual way is to turn one of the GPIO pins into a PPS. gpsd > normally sets up a /dev/pps<n> to go with a serial port. There should be a > way to tell GPSD to use /dev/pps0 rather than set up a new one. I don't know > how to do that, but that's what you should be looking for what scanning the > gpsd documentation. From the brief flamewar that seems to have ensued from my asking the question, such a feature would be implemented over the maintainer’s dead body… A simple symlink of /dev/pps1 to the one you want it to use seems to work, though it is a clearly a hack. > > If gpsd is setting up /dev/pps1, it won't work. That internal signal doesn't > go anywhere. > > ------------- > > My notes from setting up a Pi, non gpsd: > > # PPS via gpio > # > https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.satsignal.eu%2Fntp%2FRaspberry-Pi-NTP.html%23easy&data=02%7C01%7Crgovostes%40whoi.edu%7C39146838a40e4910e20208d859dc39b0%7Cd44c5cc6d18c46cc8abd4fdf5b6e5944%7C0%7C0%7C637358150270275800&sdata=yKWT9t33FvblBfKuufUPTCIL8aoqVxFvDmpS%2F6jqTeE%3D&reserved=0 > vi /boot/cmdline.txt > remove the chunk(s) with ttyAMA0 > vi /boot/config.txt > add new line: dtoverlay=pps-gpio,gpiopin=18 > pin 4 on Adafruit GPS HAT > vi /etc/modules > add new line: pps-gpio > vi /etc/inittab > run raspi-config Interfacing-Options/Serial > comment out getty line for ttyAMA0 (at bottom) > > The GPIO pin numbering is different from the chip/hardware pin numbering. > > When this gets sorted out, somebody should write a HOWTO for using chrony and > gpsd on a Pi. > > > -- > These are my opinions. I hate spam. > > > > > -- > To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org > with "unsubscribe" in the subject. > For help email chrony-users-requ...@chrony.tuxfamily.org > with "help" in the subject. > Trouble? Email listmas...@chrony.tuxfamily.org. >