Regarding SMART mode of parallax GPS

Mayank

I am using Parallax GPS module. Its RAW mode works fine, but I am unable to work with SMART mode, the problem being the GPS Module has only single pin for serial communication named as SIO, while my microcontroller or any such device has two separate pins for serial communication. So what will be the schematic of it?

Moreover I am unable to understand the format of the command to be sent in SMART mode. Can anybody plz suggest me thru one example?

plz its very urgent...

Peter Verkaik

I wrote·a Javelin class for smartmode.
http://forums.parallax.com/showthread.php?p=791719
If you understand java you should have no trouble understanding it.

regards peter

Chris Savage

Is your microcontroller capable of bi-directional communication serially on any I/O pin?

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Engineering

Peter Verkaik

Here is how to connect:

 Two pins:  o----RxPin---+----GpsPin---o
                         |
                  [noparse][[/noparse]1k ohm resistor]
                         |
            o----TxPin---+

            In this case there are seperate receive uart and transmit uart
            and anything sent is directly received (local echo)

regards peter

Mayank

but again when one will send request thru tx line.. won't it come back to rx again..??

Peter Verkaik

Yes it will (local echo) and therefore
you must filter this echo out.

Either stop the receiver before transmitting, or clear
the receive buffer directly after finishing transmitting.

regards peter

Mayank

thnx.. its working now.. well plz tell me what is the concept behind adding the resistance in between............. [noparse]:)[/noparse]

Chris Savage

Hello,

Without the resistor the TX line of your MCU would be directly driving against the GPS line when it was transmitting data. You could have a direct short without it.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Engineering