Two devices one port.

Using Arduino Project Guidance
1

I've been working with a Mega where I've had the luxury of more serial ports than I need. I'm thinking of downgrading to Arduino Uno or even a mini-pro just to save space and free up my mega for new projects.

My question is this, so far I've been using two ports, one for displaying stuff to to the screen (serial.print() etc) and one for reading in data from a GPS module. Do I really need two ports? The GPS module just vomits out data continuously, I never write to it, I only ever read. The other port is used only for writing to the screen. Is there anything stopping me from splitting the port? just connecting the GPS tx line to the arduino rx line, and leaving the arduino tx line free for writing?

Secondly, I know the serial port is used when uploading sketches to the board, if I connect my GPS module to this port, is the fact that it tends to continuously spew data even without being asked going to effect the arduino during a sketch upload?

Thanks

2

Secondly, I know the serial port is used when uploading sketches to the board, if I connect my GPS module to this port, is the fact that it tends to continuously spew data even without being asked going to effect the arduino during a sketch upload?

Yes.
You will need to switch it out during upload.

You can split the port in the way but it will only work at the same baud rate. You will probbly have to switch out the RX pin as well or at least make sure your GPS can over ride the USB / serial chip.

3

Perhaps you could use SoftwareSerial for the GPS input?

4

Thanks for your suggestions guys, I have tried SoftwareSerial before, it works, but seems to be a bit heavy on the processing - it slows down some of the other things the device is doing.

5

Allow me to introduce the...

...and the...
http://www.pjrc.com/store/teensy.html
http://www.pjrc.com/store/teensy_pins.html
http://www.pjrc.com/store/teensypp.html
http://www.pjrc.com/store/teensypp_pins.html

Note: I remember all three boards having a USART but you should check before buying.