Problem Sending Serial Data Between Arduino And ATtiny Back And Forth

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Introduction

When working with microcontrollers, serial communication is a crucial aspect of programming and debugging. In this article, we will focus on the problem of sending serial data between Arduino and ATtiny13. This bare-bone communication is essential for understanding the basics of serial communication and can be applied to more complex projects in the future.

Understanding the Components

Before we dive into the problem, let's understand the components involved:

  • Arduino Nano: A popular microcontroller board based on the ATmega328P. It is powered by a USB cable from the PC and is widely used for prototyping and development.
  • ATtiny13: A small, low-power microcontroller from Atmel (now part of Microchip). It is a great choice for small projects and is often used in wearable electronics and IoT applications.

The Problem

The problem lies in establishing a reliable serial communication link between the Arduino Nano and the ATtiny13. The Arduino Nano is connected to the PC via a USB cable, and the ATtiny13 is powered separately. The goal is to send data from the Arduino to the ATtiny13 and vice versa.

Serial Communication Basics

Before we proceed, let's cover some basic concepts of serial communication:

  • Serial Communication: A method of transmitting data one bit at a time over a single communication channel.
  • UART (Universal Asynchronous Receiver-Transmitter): A hardware component that handles serial communication.
  • Baud Rate: The speed at which data is transmitted over the serial communication channel.

Arduino Code for Serial Communication

To establish a serial communication link between the Arduino Nano and the ATtiny13, we need to write code for both boards. Here's an example code for the Arduino Nano:

void setup() {
  Serial.begin(9600); // Set the baud rate to 9600
}

void loop() {
if (Serial.available() > 0) {
char c = Serial.read();
Serial.println(c); // Send the received character back to the PC
}
}

This code sets the baud rate to 9600 and checks for incoming serial data. If data is available, it reads the character and sends it back to the PC.

ATtiny13 Code for Serial Communication

For the ATtiny13, we need to use the USART library to handle serial communication. Here's an example code:

#include <avr/io.h>
#include <avr/interrupt.h>

#define BAUD 9600
#define BAUD_ERROR 0.1


void init_usart(void) {
// Set baud rate
UBRRH = (uint8_t) ((BAUD / 16) | (BAUD_ERROR << 5));
UBRRL = (uint8_t) (BAUD % 16);


// Enable receiver and transmitter
UCSRB = (1 << RXEN) | (1 << TXEN);


// Enable interrupt on receive complete
UCSRB |= (1 << RXCIE);
}


ISR(USART_RX_vect) {
// Read incoming data
char c = UDR;


// Send the received character back
UDR = c;
}


int main(void) {
init_usart();


while (1) {
// Wait for incoming data
while (!(UCSRA & (1 << RXC)));
}
}

This code initializes the USART module, sets the baud rate, and enables the receiver and transmitter. It also enables the interrupt on receive complete and reads incoming data in the interrupt service routine.

Troubleshooting

If you're experiencing issues with serial communication, here are some troubleshooting steps to follow:

  • Check the baud rate: Ensure that the baud rate is set correctly on both boards.
  • Verify the serial connection: Use a serial monitor or a terminal emulator to check if the serial connection is established.
  • Check for hardware issues: Ensure that the serial pins are connected correctly and that there are no hardware issues.

Conclusion

Q: What is the most common issue when trying to send serial data between Arduino and ATtiny?

A: The most common issue is setting the baud rate incorrectly on both boards. Make sure to set the baud rate to the same value on both boards and verify that it is set correctly.

Q: How do I troubleshoot serial communication issues between Arduino and ATtiny?

A: To troubleshoot serial communication issues, follow these steps:

  1. Check the baud rate: Ensure that the baud rate is set correctly on both boards.
  2. Verify the serial connection: Use a serial monitor or a terminal emulator to check if the serial connection is established.
  3. Check for hardware issues: Ensure that the serial pins are connected correctly and that there are no hardware issues.

Q: Why is my ATtiny13 not receiving serial data from the Arduino?

A: There could be several reasons why your ATtiny13 is not receiving serial data from the Arduino. Here are a few possible causes:

  1. Incorrect baud rate: Ensure that the baud rate is set correctly on both boards.
  2. Serial pins not connected correctly: Verify that the serial pins are connected correctly on both boards.
  3. Hardware issues: Check for any hardware issues that may be preventing the serial communication.

Q: How do I send data from the ATtiny13 to the Arduino?

A: To send data from the ATtiny13 to the Arduino, you can use the UDR register to send data over the serial communication channel. Here's an example code snippet:

#include <avr/io.h>
#include <avr/interrupt.h>

#define BAUD 9600
#define BAUD_ERROR 0.1


void init_usart(void) {
// Set baud rate
UBRRH = (uint8_t) ((BAUD / 16) | (BAUD_ERROR << 5));
UBRRL = (uint8_t) (BAUD % 16);


// Enable receiver and transmitter
UCSRB = (1 << RXEN) | (1 << TXEN);


// Enable interrupt on transmit complete
UCSRB |= (1 << TXCIE);
}


ISR(USART_TX_vect) {
// Send data over the serial communication channel
UDR = 'A';
}


int main(void) {
init_usart();


while (1) {
// Wait for transmit complete
while (!(UCSRA & (1 << TXC)));
}
}

Q: How do I receive data from the Arduino on the ATtiny13?

A: To receive data from the Arduino on the ATtiny13, you can use the UDR register to receive data over the serial communication channel. Here's an example code snippet:

#include <avr/io.h>
#include <avr/interrupt.h>

#define BAUD 9600
#define BAUD_ERROR 0.1


void init_usart(void) {
// Set baud rate
UBRRH = (uint8_t) ((BAUD / 16) | (BAUD_ERROR << 5));
UBRRL = (uint8_t) (BAUD % 16);


// Enable receiver and transmitter
UCSRB = (1 << RXEN) | (1 << TXEN);


// Enable interrupt on receive complete
UCSRB |= (1 << RXCIE);
}


ISR(USART_RX_vect) {
// Receive data over the serial communication channel
char c = UDR;


// Process the received data
if (c == 'A') {
// Process the data
}
}


int main(void) {
init_usart();


while (1) {
// Wait for receive complete
while (!(UCSRA & (1 << RXC)));
}
}

Q: What are some common pitfalls to avoid when working with serial communication between Arduino and ATtiny?

A: Here are some common pitfalls to avoid when working with serial communication between Arduino and ATtiny:

  1. Incorrect baud rate: Ensure that the baud rate is set correctly on both boards.
  2. Serial pins not connected correctly: Verify that the serial pins are connected correctly on both boards.
  3. Hardware issues: Check for any hardware issues that may be preventing the serial communication.
  4. Not using a serial monitor or terminal emulator: Use a serial monitor or terminal emulator to verify that the serial connection is established.

Conclusion

In this article, we covered some frequently asked questions related to sending serial data between Arduino and ATtiny. We discussed common issues, troubleshooting steps, and code snippets for sending and receiving data over the serial communication channel. By following these guidelines, you should be able to establish a reliable serial communication link between Arduino and ATtiny.