Re: Help needed to configure and compile gpsd to run on a Raspberry Pi 4 and NOT use systemd

[Mick Durkin]

Hi Gary,

Next installment.

To your question about the gps module; it is a 3.3v device and has the
following pins which connect to the Pi:-
GPS         Pi
+3.3v   -> Pin 1  3V3 power
Gnd    ->  Pin 6 ground
Tx     -> Pin 10 GPIO15 (RXD)
Rx     -> Pin 8 GPIO14 (TXD)
PPS    -> Pin 12 GPIO18 (PCM_CLK)

The voltage is correct and the connections are as detailed. We were
seeing good data on cgps, so the serial output is working.

Mike Simpson made a suggestion to add "dtoverlay=disable-bt" to
/boot/firmware/config.txt and said that might remove bluetooth support
and allow us to use "/dev/ttyAMA0". We were aware of this earlier, but
the reference we saw said it applied to the Pi 3 model, so we had
ignored it. This time we added this to the config.txt and rebooted.
Now, as Mike predicted, the module is seen connected to ttyAMA0 as you
wanted.

We ran tests again similar to last time, skipping the scons stuff, as
we had not changed gpsd itself. We included some -nN -D4 logging  to
show what was going on and then ran it again in deamon mode with no
logging and captured gpsdebuginfo. We ran ppscheck against ttyAMA0,
which said it mapped to pps1 with no output. ppscheck against pps0
showed pps signals being detected.

A full log is attached.

BR

Mick

retest.log
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