problem with ublox gps

[Ttelmah]

Your best option, is to switch to a 3v PIC, and run everything at 3.3v.

SD can then be directly connected.

GPS can talk both ways.

etc. etc..

Currently it is like trying to mix Whitworth threads and metric. It can be done with the right adapters, but just trying to screw one into the other is asking for problems....

[PCM programmer]

I don't think switching to 3.3v would fix the problem. TXD only goes to
two places on the schematic. It goes to the voltage divider and to J6.
The GPS chip always runs off 3.3v. It wants 0.7 * Vdd = 2.31v for Vih.
The 50% voltage divider takes the TX signal from the dsPIC33fj128GP802
(which is a 3.3v PIC) and reduces it to 1.65v. Therefore the Vih is too low
for the GPS's RX pin.

I think, if this is how his board actually looks, he can jumper out the
10K series resistor (leaving in place the 10K pull-down), and it will
probably work. I have drawn a yellow line across the resistor that
has to be jumpered out. It's enclosed in a white circle:
http://s25.postimg.org/46c4j55i7/Arduino_GPS_shield_modified.jpg

[tatoo]

PCM programmer i did what exactly you said
(accidentally i did the same for the TX resistor except the RX resistor).

the result are the same.

I am sure that the problem is that i can not sent data to gps ( i tried to de-activate GLL )


Where can i buy a module. (full document ) and working !!for pic microcontroller ??

[PCM programmer]

Do you know if you have a wire connecting the Tx from the PIC to the
Rx on the GPS ? Have you checked the connection with an ohm-meter ?

Use an oscilloscope to look at the Rx pin on the GPS. Do you see any
signal activity when the PIC is sending commands to the GPS ?
You should see a signal. If you don't see any signal, you may have a
bad connection between the PIC and the GPS.