Thanks everyone for the input, much appreciated!
This is really a one-time ordeal, and unfortunately I need the project wrapped up next week so I'm trying very hard to avoid needed anything shipped.
I've just tried exactly what you suggested Riva, by wiring the pins 2 and 3 on the shield and sending commands through the serial monitor in a sketch with this code:
char rx_byte;
void setup() {
Serial.begin(9600);
}
void loop() {
if (Serial.available() > 0) {
rx_byte = Serial.read();
Serial.print("You sent: ");
Serial.println(rx_byte);
}
}
And absolutely no response popping up in the Serial monitor when I send single letters or numbers.
However, I thought that the shield was functional, since I used the sample code provided with the shield and it sent back "OK":
int led = 13;
void setup()
{
Serial.begin(9600);
pinMode(led,OUTPUT);
}
void loop()
{
int temp;
if(Serial.available())
{
temp=Serial.read();
if(temp=='V'){
digitalWrite(led,1-digitalRead(led));
Serial.println("OK");
}
}
}
Seems so bizarre that that my feedback test loop was not functional while the provided test code worked. The only difference is that with my feedback test loop, the Tx and Rx (pins 2 and 3) are manually wired on the female serial DB9 port on the shield and the serial monitor is monitoring via the USB to the Arduino, while in the provided test loop the serial monitor is monitoring via the USB to the DB9 port on the shield.
Any ideas what's causing this communication block?