I can't get the echo example (from https://developer.mbed.org/handbook/SerialPC) to work. Before you ask, yes, the baud rate matches, and yes, I'm selecting the right COM port. I'm using putty as my terminal. When I type characters into putty, they seem to be sent, as the RX led blinks every time I press a key on my keyboard. The issue is that they never get sent back, as nothing displays in putty. I've tried multiple boards, made sure the firmware was completely updated, and made sure to install the windows USB serial driver. Is anyone else having this issue? I'm using the latest version of the mbed library. Any help would be greatly appreciated!

Seth,

I have tried the above example and have verified it working with a KL25Z. The code from the example page will only run once on reset, you may need to press the reset button to get the code to run, this however will cause putty to disconnect. Might I suggest using the following code instead?

#include "mbed.h"              
 
Serial pc(USBTX, USBRX); // tx, rx
 
int main() {
    while(1){
    wait(1);
    pc.printf("Hello World!\n");
    }
}

Alternatively you could try using a terminal program that does not reset on disconnect, like CoolTerm.

Still nothing outputting to the terminal window. Maybe I just have a few bad boards?

you need install open sda driver. available in pe micro website