GPS transmitting Junk Data

[kulks]

Hi,

I have connected a GPS (SkyNav SKM53) to PC using UART to USB converter. The Tx pin of GPS is connected to Rx pin of the converter.
When i check on the hyperterminal, all i see is junk characters like below

ÿ@à€€ ”ðñ“ ÀÀüÌð
0Œ€þøüBøü‚Š „€Àpú
~€þüøÏÿŸ

I tested with different baud rates (9600 - 115200) but still getting the same junk characters and no trace of any NMEA data.

I also tried factory resetting the GPS using $PMTK104*37<CR><LF> command but still no gain.

Please advise if the module is damaged or am i missing here something..

Thanks

 

[nandhu015]

Post your settings in hyperterminal

 

[sherazi]

on some converters where they lable Rx that should be connected to Rx. I had faced such problems - just swap the pins and check ?

 

[kulks]

Post your settings in hyperterminal

Hyperterminal settings include

Baud Rate : 9600
Data bits : 8
Parity : None
Stop bits : 1
Flow Control : None

- - - Updated - - -

on some converters where they lable Rx that should be connected to Rx. I had faced such problems - just swap the pins and check ?

I tried swapping the pins as you said but still find the junk characters.

 

[jayanth.devarayanadurga]

Are you using USB to RS232 Converter or USB to TTL Converter? If your GPS module gives TTL pins for Rx and Tx then you have to use USB to TTL Converter to connect GPS module to PC. If you have connected RS232 pins of USB to RS232 Converter to TTL pins of GPS module then your module will be damaged.

 

[kulks]

Are you using USB to RS232 Converter or USB to TTL Converter? If your GPS module gives TTL pins for Rx and Tx then you have to use USB to TTL Converter to connect GPS module to PC. If you have connected RS232 pins of USB to RS232 Converter to TTL pins of GPS module then your module will be damaged.

I'm using a USB to TTL converter only.. its a "USB 2.0 to TTL UART 6PIN Module Serial Converter CP2102"

 

[jayanth.devarayanadurga]

Distance between MCU board and PC?

 

[kulks]

Distance between MCU board and PC?

few meters..

I just found that it could be because of baudrate or any other misconfiguration..Its a skynav SKM53 GPS withe NMEA -0183 format.

Could anyone please tell me how do I reset the GPS to default factory settings. I tried $PMTK104*37<CR><LF> but it didn't work..

 

[jayanth.devarayanadurga]

TTL communication works for few meters?

 

[sherazi]

few meters..

I just found that it could be because of baudrate or any other misconfiguration..Its a skynav SKM53 GPS withe NMEA -0183 format.

Could anyone please tell me how do I reset the GPS to default factory settings. I tried $PMTK104*37<CR><LF> but it didn't work..

if you are getting junk data or your connection isnt correct you wont be able to make it to default-
check the manual and look for default config values such as default baud and stuff.

 

[nandhu015]

As per the datasheet

The serial connections are at
2.85V LVTTL logic levels, if need different voltage
levels, use appropriate level shifters.

Is level shifter added between module and converter. If not try with level shifter