EM408 & SD Logomatic

GPS/GNSS Development Boards
1

I just got the SD logomatic and the EM408 gps unit. I would simply like to log the NMEA sentence from the GPS to the micro SD card.

I can see the NMEA sentences just fine on my computer via GPS Demo Board and hyperterminal @ baud 4800.

I have the SD card config @ mode = 0 and BAUD = 3.

I hook up the TX line of the GPS to the RXI0 input on the SD logger and i can see the buffer lights flashing to let me know that it’s writing but then when i open the files they are all giberish :frowning:

Do i need extra component to convert the output of the GPS into something the SD logomatic can take? Like serial to TTL etc? If so what is the appropriate sparkfun item to do it?

thanks!!!

2

please make sure that the baud range and voltage are ok.

the voltage should be 3.3V TTL and baud rate should be 4800 (i think)

3

Sorry im still a bit confused

The SD logomatic is powered from the SFE Lithium 2000 mAh battery. I think it’s at 3.7V.

Since i have nice serial data coming out of the SFE GPS demo board what should i do to get the SD logomatic to log that serial data?

Thanks!

4

To answer my question:

I used the BrainStem S13-SERIAL-INT-CONN to convert serial to TTL

http://www.acroname.com/robotics/parts/ … -CONN.html

I hooked up the TTL out of the brainstem TTL unit to the RXI0 of the logomatic

And the TTL in of the brainstem TTL unit to the TXI0 of the logomatic

and finally was able to power the brainstem TTL unit directly off the 3.3v of the logomatic as well.

Using the SFE 2000mAh lithium battery (powering the logger and TTL converter) iv been logging NMEA sentenses at 1 Hz for over 1.5 days.