Hi, not sure if this is a hardware or a programming issue, so I'll put it here for now...
I'm working with an ATMEGA328 chip on a breadboard. I'm using the Arduino library for easy coding within Atmel Studio (and an ISP MKii for programming). I have no way to easily debug my code short of flashing an LED, so I came up with the idea to use the RX and TX pins of the ATMega328 to print out feedback and plug them into my Arduino Mega, since it has multiple UARTs, which I can then listen on port 3 and output the results through 0 to the serial monitor. Only one problem... I'm only getting garbage back...
Here's my code on the Atmega328 - just send a simple hello
#include <Arduino.h>
int testLED = 2;
void setup() {
Serial.begin(9600);
delay(3000);
pinMode(testLED, OUTPUT);
}
void loop() {
Serial.println("hello");
delay(1000);
}
...And this is the Arduino Mega - receive the hello and print it to the serial monitor
void setup() {
Serial.begin(9600);
Serial3.begin(9600);
delay(1000);
Serial3.setTimeout(500);
delay(1000);
Serial.println("Ready...");
}
void loop() {
Serial.print("bytes available: ");
Serial.println(Serial3.available());
if(Serial3.available() > 0) {
String s = Serial3.readString();
Serial.println(s);
}
delay(3000);
}
The Output
Ready...
bytes available: 20
⸮TY)⸮TY)⸮TY)⸮T[)⸮T[)⸮T[)
bytes available: 20
⸮T[)⸮T[)⸮TY)⸮TY)⸮TY)⸮TY)
bytes available: 20
⸮TY)⸮T[)⸮T[)⸮T[)⸮T[)⸮TY)
bytes available: 20
⸮T[)⸮TY)⸮T[)⸮TY)⸮TY)⸮TY)
bytes available: 20
⸮T[)⸮TY)⸮T[)⸮T[)⸮T[)⸮T[)
bytes available: 20
⸮TY)⸮T[)⸮TY)⸮T[)⸮TY)⸮T[)
bytes available: 20
⸮TY)⸮T[)⸮TY)⸮T[)⸮TY)⸮TY)
etc...
Some extra details:
- ATMega328 chip on a breadboard
- 16MHz External Crystal
- Fuses: Extended 0xFF, High 0xD9, Low 0xE7
- Pin 3 of ATMega328 connected to pin 15 of Arduino Mega
- 9600 baud rate selected on serial monitor
Things I've tried:
Connect the atmega328 chip to Serial ports 1-3 on the Mega
Other baud rates (faster and slower)
10k pullup resistors on the tx/rx lines
SoftwareSerial (On the atmega328 side)
Using the 8MHz internal osc (with and without div8)
Make sure vcc has bypass caps
Power from Arduino / Power separately (Yes ground is connected between both)
Question: Why am I receiving garbage instead of the expected 'hello'?
