Question

open atmell studio and write an assembly program that toggels a 8 leds for differnt collor connected to portB with a custom delay time i want the code of this program

Answer 1

NOTE:- This is not as same as above but it is the c programme that i have written 2 months before you can read this and i hope you will get some help

LEDs are connected to PORTC and current limiting resistors are used to limit current through them. 16 MHz crystal is used to provide clock for the Atmega32 microcontroller and 22pF capacitors are used to stabilize the operation of crystal. The 10µF capacitor and 10KΩ resistor is used to provide Power On Reset (POR) to the device. When the power is switched ON, voltage across capacitor will be zero so the device resets (since reset is active low), then the capacitor charges to VCC and the reset will be disabled. 30^th pin (AVCC) of Atmega32 should be connected to VCC if you are using PORTA, since it is the supply voltage pin for PORT A.

Atmel Studio C Program

#ifndef F_CPU
#define F_CPU 16000000UL // 16 MHz clock speed
#endif

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

int main(void)
{
  DDRC = 0xFF; //Nakes PORTC as Output
  while(1) //infinite loop
  {
    PORTC = 0xFF; //Turns ON All LEDs
    _delay_ms(1000); //1 second delay
    PORTC= 0x00; //Turns OFF All LEDs
    _delay_ms(1000); //1 second delay
  }
}

• DDRC = 0xFF makes all pins on PORTC as output pins
• PORTC = 0xFF makes all pins on PORTC Logic High (5V)
• PORTC = 0x00 makes all pins on PORTC Logic Low (0V)
• _delay_ms(1000) provides 1000 milliseconds delay.
• while(1) makes an infinite loop

You have seen that PORT registers are used to write data to ports. Similarly to read data from ports PIN registers are used. It stand for Port Input Register. eg : PIND, PINB

You may like to set or reset individual pins of PORT or DDR registers or to know the status of a specific bit of PIN register. There registers are not bit addressable, so we can’t do it directly but we can do it through program. To make 3^ed bit (PC2) of DDRC register low we can use DDRC &= ~(1<<PC2). (1<<PC2) generates the binary number 00000100, which is complemented 11111011 and ANDed with DDRC register, which makes the 3^ed bit 0. Similarly DDRC |= (1<<PC2) can be used set the 3^ed bit (PC2) of DDRC register and to read  3^ed bit (PC2) we can use PINC & (1<<PC2). Similarly we can set or reset each bit of DDR or PORT registers and able to know the logic state of a particular bit of PIN register.