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| author | Eric S. Raymond <esr@thyrsus.com> | 2005-07-11 13:42:36 +0000 |
|---|---|---|
| committer | Eric S. Raymond <esr@thyrsus.com> | 2005-07-11 13:42:36 +0000 |
| commit | ec431ba52ff66b8f2f25fb865913dd2616bcc5d1 (patch) | |
| tree | 8325d430f497b6535af51245814197bbc08da673 /HACKING | |
| parent | 93dd4d46bf2d242e4dcd759b6584f8f65d82c99b (diff) | |
| download | gpsd-ec431ba52ff66b8f2f25fb865913dd2616bcc5d1.tar.gz | |
Configure DBUS correctly.
Diffstat (limited to 'HACKING')
| -rw-r--r-- | HACKING | 9 |
1 files changed, 7 insertions, 2 deletions
@@ -494,8 +494,13 @@ initializer method is called immediately. A good thing to send from the NMEA initializer is probe strings. These are strings which should elicit an identifying response from the GPS that -you can use as a trigger string for a native-mode driver. This is how -we detect SiRF chips (see step 5 under autoconfiguration above). +you can use as a trigger string for a native-mode driver. + +Don't worry about probe strings messing up GPSes they aren't meant for. +In general, all GPSes have rather rigidly defined packet formats with +checksums. Thus, for this probe to look legal in a different binary +command set, not only would the prefix and any suffix characters have +to match, but the checksum algorithm would have to be identical. Incoming characters from the GPS device are gathered into packets by an elaborate state machine in packet.c. The purpose of this |