cant get gps module to work.... vpn1513

will85iroc

i cant get my gps module to work in request mode (not raw).... when i pull raw low it transmits the data stream... when its high the sio pin just stays high...
the datasheet says 9600 bps but i checked with my logic probe and the sio doesnt go low, my microchip toggles but nothing...
i tried parallax's old gps unit and it works fine at 2400 bps when i change the rate so i know my routines are good.

will85iroc

just fyi, i do send !gps before each command, thanks again...

will85iroc

any suggestions???

GordonMcComb

How are you connecting the SIO line to both Rx and Tx? You need an open drain I/O pin on your controller (like the BS2 and Propeller have), or else use some external logic-steering components to divert the one I/O to your Rx and Tx pins on your controller. This is usually accomplished with a pullup resistor on the Rx line, and a signal diode in series with the Tx line (cathode toward the Tx pin).

-- Gordon

erco

Did you search the forum? Here's one older thread: http://forums.parallax.com/showthread.php/143640-GPS-VPN1513-Documentation-question?highlight=vpn1513