EM-406A -> uUSB-CE5

GPS/GNSS Development Boards
1

I am wanting to test my EM-406A GPSr, does anyone know if I can connect it to a 4D uUSB-CE5 serial-USB bridge, which I already have, to test data output on a computer.

Also any recommendations on a simple application I can use to do this (Mac or Windows)?

Thanks

2

This should not be too hard, but you would need to use a Level Converter in order to do this. The GPS uses TTL level RS232 signals, so a MAX232 or equivalent would be needed to interface the two.

I have had some success in removing the MAX232 from a USB to Serial converter but this takes a lot of work and destroyed a few devices until I got one to work.

Darryl VK2TDS

3

You do not need a max232 chip. The 4D uUSB-CE5 talks at 5v already which if I read correctly is what this gps module talks at too.

What might be a concern is that the 4D uUSB-CE5 gives you 5v power directly off the usb bus. I am not that familiar with USB power, but something tells me it is not a good idea to use unregulated USB power, especially for an rf device.

4

Thanks! In that case, could I connect only the other pins (minus power+ground) between the 2 devices, and get my 5V for the GPS from a dedicated power source?

Also any suggestions on GPS test software? I have downloaded the SiRF Demo from SFE, but not sure if it outputs NMEA data, so any alternatives would be great.

5

If you just want to see the NMEA data coming out of the module, you could use minicom, or the built in screens command line app in OS X:

http://www.tigoe.net/pcomp/resources/ar … 0749.shtml

You could use a separate supply, but you need a common ground. According to this page:

http://wiring.org.co/learning/libraries … oning.html

You will connect pin 1 and 2 to the appropriate pins of your separate power supply, and 3, 4, and 5 to the appropriate pins usb serial unit.

Please note you should triple check what I have said too. This should be fine, but there’s always the chance I could have misinterpreted or missed something altogether and I don’t want to be held responsible for frying that nice 60$… I don’t even risk that type of money on a good steak!

6

Thanks for your help macpod. I tried your suggested wiring and it seemed to work, I also tried grouping the grounds together, and finally running off the USB power, and all seems well.

I discovered that the SiRF Demo application I have can output NMEA data, as well as showing other useful stuff like satellites in view.

So far, the GPS is spitting out NMEA data when connected, but I have been unsuccessful in acquiring a GPS fix…no blinking LED yet. After leaving it on for a while it will ‘see’ several satellites, has locked onto 1 or 2, but has yet to lock on and ‘use’ any, so no position yet.

As I found when I bought my Garmin GPSr, it was unable to get a fix until I took it outdoors for the first time, so tomorrow I’ll take my setup to the park, and hope it works!

7

Just if anyone is wondering, tested GPS outdoors, and it got a fix straight away, so can confirm that the EM-406A (be sure to connect both GPS grounds) plugged into uUSB-CE5 to USB port works fine, and the SiRF Demo is a great application for seeing whats going on.

8

If you like the SiRF demo you will love ucenter from ublox. You can download it here:

http://www.ublox.com/en/evaluation-tool … enter.html