Venus GPS with SMA Connector

GPS/GNSS Development Boards
1

I received my Venus GPS dev board a few weeks ago and finally started playing with it today. It should be really simple to get working. But I couldn’t get it to work properly, maybe I’m missing something…

I connected it to my computer serial port running serial communicator software to see what’s coming out of the Venus. Previously I’d hooked up my old handheld GPS this way at 4800 baud (no parity, 8 byte, 1 stop bit) and I would see proper NMEA sentences from it so I know this setup works. When I connect the Venus and switch the program to 9800 baud all I get is garbage (crazy sets of random characters every second).

I’ve tried various baud rates. I initially connected 3.3V, ground, and Tx. Then I added VBat at 3.3V and connected Rx too. Each time still nothing legible (just garbage). I downloaded the GPS Viewer software. Still garbage.

Am I missing something or did I end up with a faulty unit? Any suggestions?

I also tried with/without the antenna recommended by Sparkfun.

2

You are using a level shifter such as the [RS232 Shifter SMD or a TTL compatible device like the [FT232RL Breakout Board between the computer and the GPS module, right?

The Venus634FLPx requires use of a 3.3 volt TTL UART connection or level shifter / adaptor between it and a computer since computer UARTs are typically 5 to 12 volt level TTL on the TX & RX lines.

Also make sure that your PC UART is configured with:

Data 8 bits

Stop 1 bit

No Parity

No Handshaking (aka software or hardware flow control)](SparkFun USB to Serial Breakout - FT232RL - BOB-12731 - SparkFun Electronics)](http://www.sparkfun.com/commerce/product_info.php?products_id=449)

3

You do need a TTL converter, and I would run the software (GPS viewer / Skytraq 0.4.4xx) from the product page.

I’m using a FTDI 3.3v breakout http://www.sparkfun.com/commerce/produc … ts_id=8772 (these are very convenient) with some M/F jumpers http://www.sparkfun.com/commerce/produc … ts_id=9140 - “Blk” gets ground, then skip, then 3.3v, then Tx (to Rx on the Venus) and Rx (to Tx on the Venus).

Came right up in the GPS viewer.

To find com ports I keep a link to windows device manager to find com ports (to a batch file with :

set devmgr_show_nonpresent_devices=1 

cd %systemroot%\system32 

start devmgmt.msc

since I can turn on nonpresent devices and delete old and orphans

4

OK, I’ll give the TTL converter a try and post how it goes.

5

Yep, bought a Max232 and a couple capacitors and the Venus is sending info! Actually, it’s always been sending info, but now I can read it!

Thanks tz and TRON.