Hands On AVR

ArduinoISP

Arduino can be used as an In-system programming (ISP) interface for the ATtiny and ATmega microcontrollers.

Here are step-by-step instructions on how to program an attiny13 with an LED blinking program:

• On the Arduino, the ArduinoISP code must be running. Open the Arduino IDE -> examples -> ArduinoISP and write.
• Build the circuit as shown above. Pins are documented in the source code. Use a 470Ω resistor between PB4 (that's pin 3 on the attiny13) and the LED.
• Install AVR toolchain: Windows, Mac
• Compile this code:

/*
hello, LED!

attiny13 Pins:

1: RESET (Arduino 10)
2: NC (not connected)
3: R (470Ω) to LED to GND
4: GND (Arduino Gnd)
5: MOSI (Arduino 11)
6: MISO (Arduino 12)
7: SCK (Arduino 13)
8: VCC (Arduino 5V)

*/

#define F_CPU 9600000	// Define software reference clock for delay duration

#include <avr/io.h>
#include <util/delay.h>

#define LED PB4 // Define led output on PB4

uint16_t d; // delay variable

/**
 * delay
 *
 * @param ms duration in milliseconds
 *
 */
void delay_ms(uint16_t ms)
{
	for (uint16_t i = 0 ; i < ms ; i++) {
 		_delay_ms (1); // Loop delay
 	}
}

int main()
{
	d = 250; // delay time in ms
	DDRB |= (1 << LED); // Set direction to output for LED
	
	for (;;) {	// forever
		PORTB ^= (1 << LED);
		delay_ms(d);
	}
	return 0;
}

• run avrdude, make sure you choose the correct USB port and speed, i gave the program the name 'led.hex':

 avrdude -P COM9 -b 19200 -c avrisp -p t13 -U flash:w:led.hex:i

• enjoy the blinking LED!

AVR

more on AVR soon.