Led Blink Code – Hello World Led using atmega16 in C

Configuring the microcontroller before running it the first time:

Fuse bytes : high and low
Program them once before you start using the micro-controller
Disable JTAG to free up PORTC for normal use
Set the correct clock clock option
With the hardware set up, run in Command Prompt :
For 1MHz internal clock:
vrdude -c usbasp -P usb -p m16 -U hfuse:w:0xd9:m -U lfuse:w:0xe1:m
For 16MHz external crystal:
vrdude -c usbasp -P usb -p m16 -U hfuse:w:0xc9:m -U lfuse:w:0xef:m
Refer to datasheet sections on “System clock and clock options” and
“Memory programming” for other clock options and their settings.
Setting the wrong fuse values may render the uC unusable

How We will Program it:

Blink an LED
– Choose a port and a pin
– In the code
1. Set pin direction to output
2. Set pin output to high
3. Wait for 250ms
4. Set pin output to low
5. Wait for 250ms
6. Go to 2
Relevant registers :
DDR  – set pin data direction
PORT – set pin output
PIN  – read pin input

Blink.C – Code in C Language:

#include <avr/io.h> // contains definitions for DDRB, PORTB
#include <util/delay.h> // contains the function _delay_ms()
int main(void)
{
DDRB = 0b11111111; // set all pins on PortB to output
while(1)
{
PORTB = 0b00000001; // Set PortB0 output high, others low
_delay_ms(250); // Do nothing for 250 ms
PORTB = 0b00000000; // Set all of them low
_delay_ms(250); // Do nothing for 250 ms
}
return 0;
}
/* DDRB is a 8-bit register which sets direction for each pin in PortB
PORTB decides output for output pins
0b – prefix for binary numbers, 0x – hex, no prefix – decimal
Thus, 15 = 0xf = 0b1111
*/