Gps multiplexing and raeding directly from com port

[nitro_67]

Is it possible to read data directly from com2 port (device is connected to
com4 and beacuse of multiplexing function is visible as com2, too), without
using GPS intermediate driver. If it's posiible please give me some hints,
how can I do this.

 

[Christian Resma Helle]

You can read from the multiplexer port (program port) that the GPS
intermediate driver uses

 

[Christian Resma Helle]

For me, the most performance effective way to do this is by polling the COM
port using the native ReadFile function. You'll have to parse the NMEA
strings yourself though.

 

[Bjørn Brox]

Christian Resma Helle skrev:

For me, the most performance effective way to do this is by polling the
COM port using the native ReadFile function. You'll have to parse the
NMEA strings yourself though.

Is there any difference in reading the virtual comport or the real comport?
I guess no.

 

[Christian Resma Helle]

Well if you read from the real port then only one programs can read from it.
If you read from the multiplexer port, then other programs can access the
GPS device same time as you do. If your applicaiton integrates with 3rd
party navigation solutions then you would probrably want the navigation
system to also use the GPS device

 

[Bjørn Brox]

Christian Resma Helle skrev:

Well if you read from the real port then only one programs can read from it.
If you read from the multiplexer port, then other programs can access the
GPS device same time as you do. If your applicaiton integrates with 3rd
party navigation solutions then you would probrably want the navigation
system to also use the GPS device

I know, but question was based on performance and the fact that you have
to parse NMEA strings anyhow.

 

[Christian Resma Helle]

Actually, I don't think there would be any difference (or at least any
noticable difference) with reading from the GPS API or directly to the
multiplexer port through p/invoking ReadFile (even if you have to parse it
yourself). But there will be a difference if you use the SerialPort class of
..NET for reading from the multiplexer port.

There are probrably certain devices with built-in GPS devices that don't
work with the GPS API (e.g. HTC P3300 with Windows Mobile 6.0). I had to
make a GPS based solution using this device before and I could not succeed
with using the GPS API, so i tried using the SerialPort and parse it myself.
That gave me some serious performance issues and made the device
unresponsive. That's why i suggested p/invoking ReadFile instead.

 

[Christian Resma Helle]

Reading the GPS port on the HTC P3300:
http://nativemobile.blogspot.com/2007/01/reading-gps-port-on-htc-p3300.html