GPS on the Neo 1973
The Neo1973 device contains an integrated GPS. The particular device is marketed as an AGPS, and there is some discussion available as to what significance that "A" might have.
In the very early shipment to 50 Phase 1 developers, a binary-only program for talking to the the GPS was accidentally included in /home/root/DM2/gps, (and presumably, the same binary would function on a P0 device).
There is an ongoing effort to write a Free Software program that could be used instead of this binary-only program. See Hammerhead/Protocol for details and the latest status.
Quick test (driver output to console) on Neo1973 Phase 1
Main article: Getting GPS console output with gllin
To get the output of this driver, read the file /tmp/nmeaNP (it is actually a pipe, not a file). The simplest way is to open another ssh connection to the phone and use cat:
This way it is possible to see the first results very easily.
Binary Daemon GLLIN
For those few with the binary driver in the meantime, Pavel Machek provides the following script for recording an NMEA stream from the binary program.
#!/bin/sh echo 1 > /sys/class/leds/gta01\:vibrator/brightness killall gllin cat sleep 1 echo 0 > /sys/class/leds/gta01\:vibrator/brightness mknod /tmp/nmeaNP p cat /tmp/nmeaNP >> /tmp/gps.nmea & /home/root/DM2/gps/gllin -low 5 /home/root/DM2/gps/gllin -periodic 3
The binary program was compiled to OABI format which now is obsolete as OM2007.2 builds are in EABI format. You can still run the binary with chroot. Bartek Zdanowski wrote an aticle how to run GPS receiver. Alternativly ld-linux can be used to do the trick:
The ld-linux trick
you need the following files:
bin/gllin bin/gllin.sh lib/ld-linux.so.2 lib/libc.so.6 lib/libgcc_s.so.1 lib/libm.so.6 lib/libnss_dns.so.2 lib/libnss_files.so.2 lib/libpthread.so.0 lib/libresolv.so.2 lib/librt.so.1 lib/libstdc++.so.6 lib/libutil.so.1
the file bin/gllin.sh contains:
#!/bin/sh `pwd`/lib/ld-linux.so.2 --library-path `pwd`/lib `pwd`/bin/gllin -low 5 test -p /tmp/nmeaNP || ( rm -f /tmp/nmeaNP && mknod /tmp/nmeaNP p ) `pwd`/lib/ld-linux.so.2 --library-path `pwd`/lib `pwd`/bin/gllin -periodic 3
be shure to start at least a `cat /tmp/nmeaNP` somewhere.
another aproach (chroot) is described in Gllin - here is also a link to a archive with all needed shared libraries in the right format.
Stack size 8864 bytes (9 KB)
means, nobody is reading on the pipe /tmp/nmeaNP, you probably forgot to start the `cat ...`.
gllin: early exit(3) in halInit()/681
is issued by the low-level hardware test but gllin works fine afterwords.
do not use the option
because gllin writes all files to /tmp then which is a bad idea. because /tmp is ram it is lost. because ram is limited the logfile will eat up your memmory.
He also succeeded at getting the Neo1973 to act like a bluetooth GPS with the following script: (Note that this script has bad problems if you run it more than once. You can get a "time traveling GPS" effect, with the GPS showing you your past position).
#!/bin/sh killall rfcomm tail mknod /dev/rfcomm0 c 216 0 echo 1 > /sys/devices/platform/s3c2410-i2c/i2c-0/0-0008/gta01-pm-bt.0/power_on sleep 1 hciconfig hci0 up name linuxgps sleep 1 sdpd sleep 1 sdptool add SP ( while true; do rfcomm listen /dev/rfcomm0 1 sleep 1 done ) & ( while true; do tail -f /tmp/gps.nmea > /dev/rfcomm0 echo 1 > /sys/class/leds/gta01\:vibrator/brightness sleep 1 echo 0 > /sys/class/leds/gta01\:vibrator/brightness done ) &
gllin sends a udp packet per nmea sentence on port 6000. this is a much cleaner aproach because using files will fill up memory or rootfs (the latter will result in the need for reflashing).
i switch off writing to /tmp/nmeaNP and logging to log/... with
the help says that -nmea is the default, fact is that gllin logs nmea sentences into ./log/<date> wich will fill up mem or rootfs for long running tests. the following python script reads the nmea sentences:
import socket s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) s.bind(('127.0.0.1', 6000)) while True: line = s.recv(1024) print line
the program just prints those to stdout but other methods are possible (i feed them into a NMEA parser).
benefits are that both programs can be started and stopped at will. none needs the other. gllin will not terminate if /tmp/nmeaNP is not there or not read from. the `cat /tmp/nmeaNP | gzip > gps.gz` is a useless idea anyway because the files in log/ (current directory) contains the NMEA data already.
The ouput from the binary driver seems to follow the NMEA standard.