Embedded programming

This code calls a blink function to make the LED blink when the push button is pressed

Settings

The first step is to connect the arduino board and to load select it in Tools, select the port, and upload the ArduinoISP sketch from examples. Then disconnect, connect the hello board to the Arduino board, reconnect to the PC, select Board and processor as Attiny44, select clock, select programmer as ArduinoISP, burn Bootloader, and finally upload the sketch.

To programme your Attiny44 with the Arduino board you'll need to install the Attiny44 plugin in the Arduino software. The steps to do this are:

Go to: File > Preferences : in the bottom of the window you will see "Additional Boards Manager URLs"
Paste the following URL: link
Clik OK and go to: Tools > Board > Board Manager
In the Board Manager list find "attiny by David A. Mellis version 1.0.2" and click installed
When the installation is finished INSTALLED will be written next to it.
Now you will find the Attiny24/44/84 in the Board menu

Once that is done you can use the Arduino Board as a programmer for the Attiny 44. To programme the Hello board using Arduino follow these steps:

Plug the Arduino board to your PC
Select the Board type ours is: Tools > Board > Arduino/Genuiono Uno
Select the port to which the Arduino board is connected: Tools > Port
Open the the ArduinoISP sketch: File > examples > Arduino ISP
Upload the code to the Arduino Board: Arrow symbol on the top left
Unplug the Arduino Board from your PC
Connect the Arduino board to the Hello Board according to the diagram

Reconnect the Arduino board to your PC
Select the Attiny board: Tools > Board > Attiny24/44/84
Select the processor: Tools > Processor > Attiny44
Select the clock frequency: Tools > clock > External 20MHz
Select the programmer: Tools > Programmer > Arduino as ISP
Burn Bootloader: Tools > Burn Bootloader
Open your code or
Upload the code to the Hello board using the Arduino as a programmer: Sketch > Upload using programmer
Disconnect the hello board from the Arduino Board leaving GND and Vcc to power it or power it with an FTDI cable
Test the board to see it working

Programming in C

Hello code in C language

This code does the same thing as the Arduino code. It calls a blink function to make the LED blink when the push button is pressed

#include "avr/io.h"
#include "util/delay.h"

#define LED_PIN PA7 // Define LED_PIN
#define PUSH_PIN PA2 // Define PUSH_PIN

int main(void) {

DDRA |= (1 << LED_PIN); // Configure LED_PIN (PA7) as output
DDRA &= ~(1 << PUSH_PIN); // button is input

while(1) // while infinit loop
{
if((PINA & (1 << PUSH_PIN))) // if the push button is on
blink(); // call blink function
else // else (if the push button is off
PORTA &= ~(1 << LED_PIN); // set LED_PIN low
}

}

void blink(void) // blink function subroutine (empty function)
{
PORTA |= (1 << LED_PIN); // set LED_PIN high
_delay_ms(200); // wait 500ms
PORTA &= ~(1 << LED_PIN); // set LED_PIN low
_delay_ms(200); // wait 500ms
}

Port registers

The code uses the DDRA registers to set the push-button pin as an input and the LED pin as output;
The PORTA register to set the value of the LED pin
The INA register to read the state of the push button pin

Fuse bytes

The fuses can be calculated with an online calculator as Engbedded. Fuses bits are enable if set at 0 and disabled if set at 1.The Low byte fuse set the clock value. For an external clock all the bytes are disabled.In the High fuse byte SPIEN must be enabled to allow serial programing, and RSTDISBL must be disabled to allow reprograming.The value of the fuses are:

These values must be inserted in the makefile. The extended fuse is left unprogrammed as default

Embedded programming

Programming in Arduino

Hello code in Arduino language

Settings

Programming in C

Hello code in C language

Port registers

Fuse bytes

Programming with FabISP