This is not as straight forward as it sounds...

I am using a GPS module BU353 that has a USB output. There is seamingly no way to connect USB to a Basic Stamp, but I don't want to give up... When examining the schematic, it looks like it should be possible to locate the pin that would supply 0V/5V TTL logic. I could use this pin with the SERIN command on the BS2 to read the data.

http://www.usglobalsat.com/p-62-bu-353-w.aspx

http://data.smbelsky.com/BU-353%20schematics.pdf

I tried interfacing to TP4 (page 2, middle of the right side) but it does not seem to be working. My multimeter reads the pin at ~3.3V. I unfortunately I do not own a scope.

What pin in this circuit would be the TTL transmission line?

Anyone with a good eye want to make a recommendation?

Thanks it advance!

 

I dont know if the basic stamp supports SPI bus, but if it does, you can use the SPI data and SPI clock pins from the GPS.

Thats how one would typically connect a GPS IC to a microController.

 

I'm not sure if it supports that. From searching google, I determined most users are setup using ttl serial connections.

I believe one of the ICs on the schematic are a TTL to rs232, so I feel like I should be able to get this to work.

 

I got it to work! Pin 5 on U2 worked perfectly.