Letux Kernel


You are looking at an old revision of the page GPS. This revision was created by Nikolaus Schaller.

Table of Content

How to configure and use GPS

Enable power

Wake-up GPS receiver chip

echo 0 >/sys/devices/virtual/gpio/gpio145/value
echo 1 >/sys/devices/virtual/gpio/gpio145/value

Power for the internal/external antenna

echo 2800000 >/sys/devices/platform/reg-virt-consumer.5/max_microvolts
echo 2800000 >/sys/devices/platform/reg-virt-consumer.5/min_microvolts

To power down (may draw several mA):

echo 0 >/sys/devices/platform/reg-virt-consumer.5/max_microvolts
echo 0 >/sys/devices/platform/reg-virt-consumer.5/min_microvolts

Read device file (use 9600 baud!)

stty 9600 </dev/ttyS1
cat /dev/ttyS1

If you don't see NMEA records coming every second, give another wake-up impulse (each impulse appears to toggle between standby and active).

If you don't get any satellite fix, check that the antenna is working and are powered.

Internal/external antenna detection

if the external antenna is active can be determined through

cat /sys/devices/virtual/gpio/gpio144/value  # 1=external antenna, 0=internal ant or antenna power off