Project

General

Profile

Actions

BCM4751 » History » Revision 2

« Previous | Revision 2/33 (diff) | Next »
Paul Kocialkowski, 02/16/2012 08:00 PM


Broadcom4751GPS

Files

The non-free files holding the GPS infos/code are the following:

/system/vendor/bin/gpsd
/system/vendor/lib/hw/gps.s5pc110.so
/system/vendor/etc/gps.xml
/system/etc/gps.conf

Protocol

Apparently, the protocol that is used by the chip to provide the GPS infos is MEIF. The GPSD component is in charge of translating that to standard NMEA that is sent to the gps.s5pc110.so lib via the /dev/socket/gps Unix socket, created by GPSD.

Attempts

We have written code to read data from the correct serial interface: https://gitorious.org/replicant/crespo-gps-utils

It currently doesn't work: it fails to somehow boot the chip. Though, it works after starting gpsd once and stopping it. It must be doing some kind of magic code to start the chip.

Related gps.xml parameters

We have tried to change some parameters in gps.xml to see how it behaves:

Parameter Original Changed to Result
acPortName /dev/s3c2410_serial1 /dev/s3c2410_serial42 The chip wasn't "booted"
gpioNStdbyPath /sys/class/sec/gps/GPS_PWR_EN/value /sys/class/sec/gps/GPS_PWR_EN/value2 The chip was booted
gpioNResetPath /sys/class/sec/gps/GPS_nRST/value /sys/class/sec/gps/GPS_nRST/value2 The chip was booted

Updated by Paul Kocialkowski almost 11 years ago · 2 revisions

Also available in: PDF HTML TXT