Software Serial RX line stuck being driven high?

Using Arduino Programming Questions
1

Hello All,

I am using Pins:
PB0(13) as TX
PB7(53) as RX

Chip: ATMEGA2560

Sample code below:

#include <SoftwareSerial.h>


SoftwareSerial my_Serial(53, 13, false); // RX, TX

void setup()
{
   Serial.begin(25000);
   while (!Serial);
   my_Serial.begin(38400);
   while (!my_Serial);

   my_Serial.println("test");//this works

   while(true){
      while (my_Serial.available()){
         Serial.write(my_serial.read());
      }
   }
}

I do not have this setup as a loopback or anything, I am using a second FTDI cable to connect to the software serial. TX from the 2560 works fine, but cannot receive.

No matter what I do it seems like the RX line is being forcibly driven high by the micro, I cannot even pull it up with a 1k resistor or anything.

Ideas?

2

Sample code below:

So its not all the code ?

3

theshadow124:
I do not have this setup as a loopback or anything, I am using a second FTDI cable to connect to the software serial. TX from the 2560 works fine, but cannot receive.

Post a simple diagram showing clearly how you have everything connected.

In Serial communication a Tx holds the line HIGH when the system is idle.

...R
Serial Input Basics - simple reliable ways to receive data.

4