Indictator on TX & RX pins?

I'm using a CP2102 based USB bridge in my project. I would like to have a visual indication of data throughput but I notice that the CP2102 does not appear to have any outputs to drive LED's so I'm wondering if it is possible to simply connect LED's via resistors to the TX and RX pins on the 328P, would this compromise speed or worse?


Yes you can. It will not hurt speed. Use high value resistors so there is not much load on the line, especially the load connected to the '328P Rx pin (sourced by the CP2102). The 328P can handle a high load on its Tx pin.
1K should only add 2-3mA to the load.

And to be useful you would want to wire the other end of the led/resistor to +5vdc (cathode end to arduino pin) so that a logical LOW on the data pin lights the led as TTL serial data is idle at a HIGH level on both send and receive lines.


Thanks for the help guys :slight_smile: