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From: | Frank Nicholas |
Subject: | [gpsd-dev] 20160520 - Latest Pi firmware & no serial ports |
Date: | Fri, 20 May 2016 19:13:53 -0400 |
I have a solution, and it’s non-intuitive. The link I sent above clearly states that “enable_uart=1” is if you want a UART console. However, it appears that with the latest firmware, **without** the “enable_uart=1” option, NO UARTs are created/initialized on boot up. Without the “enable_uart=1”, the devices are never created. Note that I never did a `rpi-update` - I don’t even find that command on the 2016-05-10 Raspbian Lite image. Regarding updates I did the following: 49 sudo apt update 50 sudo apt list --upgradable 51 sudo apt upgrade The following is required in “/boot/config.txt” (I have NOTHING else in “/boot/config.txt" - everything else is commented out): dtoverlay=pi3-disable-btenable_uart=1 Then from the other link sent earlier by Anthony Stirk (https://www.raspberrypi.org/forums/viewtopic.php?f=66&t=148515), you must do a `sudo systemctl mask address@hidden` to stop systemd from using the serial port (note that I haven’t removed anything like systemd, etc.) After adding the above 2 x lines to “/boot/config.txt” and rebooting, here is my output: address@hidden:~ $ ls -l /dev/ttyAMA0 crw-rw---- 1 root dialout 204, 64 May 20 22:52 /dev/ttyAMA0 address@hidden:~ $ stty -F /dev/ttyAMA0 raw 9600 cs8 clocal -cstopb address@hidden:~ $ cat /dev/ttyAMA0 $GPGGA,225404.000,3909.1291,N,08543.4894,W,2,10,0.87,227.7,M,-33.5,M,0000,0000*5D $GPGSA,A,3,01,19,24,06,22,28,17,30,03,11,,,1.51,0.87,1.24*0A $GPRMC,225404.000,A,3909.1291,N,08543.4894,W,0.01,346.44,200516,,,D*7F $GPVTG,346.44,T,,M,0.01,N,0.01,K,D*39 $GPGGA,225405.000,3909.1291,N,08543.4894,W,2,10,0.87,227.7,M,-33.5,M,0000,0000*5C $GPGSA,A,3,01,19,24,06,22,28,17,30,03,11,,,1.51,0.87,1.24*0A I’m sure this isn’t the “correct” way to make these things happen. I’m not sure what happens if you don’t have systemd (it’s been removed). For those that have removed systemd, do you now have an “/etc/inittab”? If so, is this there a “getty” line that uses "/dev/ttyAMA0”? Check for that and comment it out if it exists. I’ll do some more testing by starting from a fresh image install, following the latest HowTo, removing systemd, and see how this can be fixed if the issue still exists. Thanks, Frank |
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