I was wondering if someone might help with a problem I’m having with this gps.
I’ve been trying to get this thing to talk to the GPSViewer program without success.
I have a FTDI Basic Breakout - 3.3V board and I ran wires from a header on the Venus to a small header that is plugged into the FTDI.
I have 3.3V being sourced by the FTDI Board connected to 3.3V on the Venus and the Grounds on both boards hooked together.
I have Rx from the FTDI going to the TX on the Venus.
I have Tx from the FTDI going to the RX on the Venus.
I havn’t been able to get any data from the Venus. I’ve seen 1 time I got a partial NMEA string but since then nothing. Every now and then I see some action on the tx and rx led’s on the FTDI, but not consistant.
I get errors in the GPSViewer program occasionaly. I’ve tried several baud rates, but nothing seems to work. One time I saw the LED on the venus blinking so I assumed it found some satelites, but wouldn’t talk.
The FTDI works fine with my Arduino so I assume its not a driver issue?
Am I missing something termination wise? Any suggestions?
I have used the same setup and it does work. I have to disconnect the transmit line from the Venus and just leave the 3.3V, GND and receive line connected. If I don’t do this, Windows thinks I’m plugging in a mouse due to the data coming in on the serial port. Once it shows up under your ‘Ports’ section in the Hardware Manager, you can plug the transmit line back in and it should work.
gm:
I have used the same setup and it does work. I have to disconnect the transmit line from the Venus and just leave the 3.3V, GND and receive line connected. If I don’t do this, Windows thinks I’m plugging in a mouse due to the data coming in on the serial port. Once it shows up under your ‘Ports’ section in the Hardware Manager, you can plug the transmit line back in and it should work.
HTH,
gm
Thanks for the reply gm. I measured the voltage on the 3.3v line and its only around 2.85 or so. Its only 3.0v when I’m hooked up to the arduino. Do you think that perhaps the startup current before a lock is to high for the FTDI 3.3v board and is pulling the voltage down and not allowing the Venus to operate?
I’m pretty sure sparkfun’s ftdi usb-serial module 3.3v regulator setup only supplies 50mA… possibly less if part of that 50mA is used by the module device itself.
The venus module I made pulls around 90mA when acquiring sats, and I think about 50mA later… so yea, I imagine it could be that.
macpod:
I’m pretty sure sparkfun’s ftdi usb-serial module 3.3v regulator setup only supplies 50mA… possibly less if part of that 50mA is used by the module device itself.
The venus module I made pulls around 90mA when acquiring sats, and I think about 50mA later… so yea, I imagine it could be that.
Well there may be something to this. I tryed the GPSViewer program on my development computer and I didn’t get anything from the Venus. I tried my main computer and then I began getting feedback from the Venus.
There were times that the GPS strings would have messed up characters, but eventually would streighten out. I then tried a USB hub and then I began getting regular characters with no misses. I still cant change the baud rate or read the logger status or the firmware revision.
note:
I just checked the 3.3 V on the gps and it is now 3.1 running off of the USB hub. It was 2.8 or 2.9 on just the computer usb port.
I’m begining to wonder if I have a bad RX on the Venus. I can do a baud scan and it never finds the Venus even though it is sending GPS strings.
Any other ideas regarding the RX on the Venus? I just received this module the other day. Would really suck if its a bad RX on the GPS. Do they have any kind of warranty on purchased devices?
It must be the voltage of my USB or the current draw. Now everything is working fine and I’m able to change GPS configuration and I have the logger running and 115k baud now.