Question

Microprocessor and embedded systems

(60 คะแนน) จงอธิบายผลของการทำงานให้ code ดังต่อไปนีพร้อมทั้งเขียน comment ในทุกบรรทัด code irte commnent Ceth ne 3. cavr b.h of operetlon #define Doraemon 4 int main(void) while (1) char Nobita 8xAA; char x; char temp; temp Nobita; DDRB I (1<< (Doraemon+1)); for (x-0;x<8;x++) if (temp & ebeeeee001) PORTB I- (1<< (Doraemon+1)) PORTB &(1<<(Doraemon+1)); else temp temp>>1; if (temp) temp Nobita;

Answer 1

#include <avr/io.h>
#define Doraemon 4

int main (void)
{
while(1)
{
char Nobita = 0xAA;    // Creating a variable with value 0b10101010
char x;
char temp;
temp = Nobita; // Initializing temp with 0xAA value
DDRB |= (1 << (Doraemon+1)); // Make PORT B pin 5 as output port and other bits as input port
for (x = 0; x < 8; x++)
{
if (temp & 0b00000001)    // Checking if LSB bit of temp is '1' or not
PORTB |= (1<<(Doraemon+1)); // if LSB bit of temp = '1'then, send a value of '1' on PORTB pin 5
else
PORTB &= ~(1<<(Doraemon+1)); // if LSB bit of temp = '0' then, send a value of '0' on PORTB pin 5
temp = temp >> 1; // Shifting temp right shift by 1 bit
if (temp == 0)
temp = Nobita; // if temp becomes zero because of right shifting then, Re-assigning temp with initial value 0xAA
} // Loop for each bit of temp i.e 8 times
}   // Loop infinite times
} // end of code

Overall Program Comment
// This program send a value of '0' and then '1' continuously on pin 5,
// such that it toggles every second bit checking of temp variable