Help to setup GPS connection.

[ScaleRobotics]

For the baud rate to be timed right, PicBasic needs to told exactly what frequency the crystal is. PicBasic only allows certain crystals to be defined. Here are the settings allowed: MHz: 3(3.58) 4 8 10 12 16 20 24 25 32 33 40 48 64. Of course your chip has restrictions as well. (It max's out at 20 mhz).

If you have a 16mhz crystal, you might give it a try while you wait for a 20mhz to come in. 38400 baud works with debug out at 8 mhz, so at 16mhz I figure your 57600 might work. In the meantime, you could connect the gps to a max232 device, and change the baud lower with your computer. Then you could connect it to your pic at a lower baud rate, using a lower speed crystal. But 20mhz is highly recommended.

[mbox]

Hi,
Finally I manage to make the baudrate to 9600 with this guide http://docs.trenz-electronic.de/GlobalT ... ket_01.pdf but I have not connected it yet to PIC16F877A.
I'm going to use SERIN on PortB.0 to fetch data from GPS using 4Mz crytsal....feed back you later the result when I get back home.

regards,
mbox

[mbox]

Hi, I got a follow up question, I need to get latitude and longitude from this string
$GPRMC,053740.000,A,250.6319,N,12136.0099,E,2.69,7 9.65,100106,,,A*53. How can I achieve it using SERIN?

thanks,
mbox

[mackrackit]

You would be better off using SERIN2.
Here is a snippet from something .

SERIN2 PORTB.2,16572,[WAIT("$GPGGA"),WAIT(","),DEC2 H,DEC2 M,DEC2 S,_
        WAIT(","),DEC2 ND,DEC2 NM,WAIT("."),DEC3 NMD,WAIT(",N,"),_
        DEC3 WD,DEC2 WM,WAIT("."),DEC3 WMD]

[mbox]

You would be better off using SERIN2.
Here is a snippet from something .

SERIN2 PORTB.2,16572,[WAIT("$GPGGA"),WAIT(","),DEC2 H,DEC2 M,DEC2 S,_
        WAIT(","),DEC2 ND,DEC2 NM,WAIT("."),DEC3 NMD,WAIT(",N,"),_
        DEC3 WD,DEC2 WM,WAIT("."),DEC3 WMD]

Hi, I'm trying to understand SERIN2 command. why this code do not work when I entered "hello"?

Include "modedefs.bas"
main:
Serin2 PORTC.7, T9600, error, [WAIT("hello")]
serout2 PortC.6, T9600, ["Valid"]
goto main

error:
serout2 PortC.6, T9600, ["Invalid"]
goto main
end

regards,
mbox

[mackrackit]

I imagine many are thinking, "have you read the manual?".

Include "modedefs.bas"
Does nothing with SERIN2/SEROUT2.

T9600
Is for SERIN/SEROUT. "T" is for true mode anyways so if you are connecting directly to a PC you want INVERTED mode.

Appendix A from the manual has the modes for SERIN2. At 9600 baud the mode will be 16468. To see how that is calculated look here. http://www.picbasic.co.uk/forum/cont...SERIN2-SEROUT2

You will also want to specify a time for the GOTO LABEL "error".

Try this

SERIN2 PORTC.7, 16468,100, error, [WAIT("hello")]

The above will wait for 100 milliseconds, then GOTO "error" if "hello" is not received.

[mbox]

Hi mackrackit, thanks for the help, appreciated very much. I manage to run this code MCU to PC and use this guide http://melabs.com/resources/ser2modes.htm

main:
SERIN2 PORTC.7, 84,200, error, [WAIT("Hello")]
serout2 PortC.6,84, ["Valid",10,13]
goto main

error:
serout2 PortC.6, 84, ["Invalid",10,13]
goto main
end

I know u have given me an example, but dont really get it ,
Is there a way I could receive this value "$GPRMC,053740.000" and place it on a variable?

thanks and regards,
mbox