i-Trek and the Zaurus PDA


These are my notes regarding use of the i-Trek / Holux GM-270 card with the Zaurus. I'm using Cacko/Qt 1.23 ('Nastya').

If anyone has any problem which are not listed in this document, may I refer them to http://qpegps.sourceforge.net and specifically, http://qpegps.sourceforge.net/assets/gps_units/holux_gm_270.html.

Also see the release notes for qpegps.

People have reported 'bad Vcc' errors (in the syslog or visible with 'dmesg') when using this GPS card - see the notes on the qpegps site for answers regarding this. In my case, I didn't have 'bad Vcc' but attempting to read from the GPS device would return garbage and occasionally the command would freeze. The problem is due to an incorrect base baud rate, and a few other things that I encountered later. The gpegps release notes document suggests a few ways to fix this permanently - I was not able to get this working so I wrote a script to initialise the GPS unit and would run this before using it.

The i-Trek card is known by many other names and is recognisable by the manfid vendor and product codes, which are '0x0279', '0x950b' (do 'cardctl ident 0' to see these).

You might like to add this to your /etc/pcmcia/serial.conf:

card "iTrek GPS Card"
  manfid 0x0279, 0x950b
  bind "serial_cs"

Through experimenting, I discovered that the Zaurus gets the baud_base wrong, and also the UART type. These commands fixed it - with the card plugged in, type (as root):

setserial /dev/ttyS3 uart 16550
setserial /dev/ttyS3 baud_base 115200
stty speed 4800 
Doing 'cat /dev/ttyS3' should then return GPS data, which is immediately
recognisable as lines of text in the NMEA format ('$GPS' at the start of
the line).  I found
this webpage
very useful in interpreting the data.

If anyone would like to discuss this further, my email - obfuscated as always - is br,oo,kn,et,AT,im,ap,DOT,cc (just remove the commas and convert 'AT' and 'DOT' to '@' and '.'). I dream of a day when I might not have to do this with my email address.. spam.. grr!

Return to my homepage