I am not too familial with UART yet, and was wondering if I could some how duplicate the stream of information going to a microcontroller from a GPS. My application will be using a msp430g2553 microconltroler to communicate with a GPS module while data-logging with (OpenLog).

I have read that you should not just simply have 1 sender and 2 receivers, https://learn.sparkfun.com/tutorials/serial-communication

Any suggestions/advice will be appreciated.


You may be misinterpreting a part of that page. If you look for the text "It can be safe to connect multiple receiving devices to a single transmitting device" the diagram shows a way to connect the two that should be OK for this case:

enter image description here

A few of the warnings on the page like "you can’t pick and choose which device hears what transmission" don't really apply in your case because you do want both devices to hear all communication from the device.

A big no-no with serial communications is attempting to connect two transmit lines together, but generally feeding a transmit line to several receivers is fine as long as you pay attention to voltage levels to make sure they're within range for your microcontroller and for example don't try to connect RS232 levels to a TTL device.

  • \$\begingroup\$ Ok, thanks for the answer/reply! I was concerned that only one device would except the transmission or get split some how between the two. I was also concerned about the statement "Not really up to spec and probably frowned upon by a hardened engineer". But I guess i'm not a really a "hardened engineer" yet. \$\endgroup\$
    – xy007
    Feb 14 '15 at 0:25
  • \$\begingroup\$ @xy007 no problem and they should both receive fine, the receive inputs on a microcontroller have a pretty high impedance so it shouldn't affect your other device as long as the voltage isn't higher than the microcontroller (then it may clamp them to a lower voltage). \$\endgroup\$
    – PeterJ
    Feb 14 '15 at 0:29

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