MAKE ARDUINO DIGITAL PINS SWITCH FASTER ANYTHING USING PORT MANUPULATION

This post helps to use port manipulation technique to switch multiple ports ON or OFF at same time improves switching speed to Micro seconds.

The Arduino ide default uses the digital Write() function for ON or OFF the digital pins but if take a look at the backend code of the digital write function there is lot happening that takes lot of the time nearly 50ms delay to execute.

Since it is slow and sequential in execution we can use PORT MANIPULATION technique to speed up process. After all c code is faster than c++.

Here the avr dude compiler built in Arduino ide uses register called DDRX means “Data direction register” the “X” replaces the PORTS of atmega328pu. The DDRX replaces the pinMode () function on void setup (). In DDRB means data direction register of portB(pin 8 to 13) the direction of ‘0’ means ‘’INPUT’’ ‘1’ means OUTPUT.

The PORTX used instead of digital Write () which is used to turn on or off all port pins same time. Here the “X” means PORT NAME B, C, D. writing PORTB replace digitalWrite(), Assigning the value ‘1’ means ‘’HIGH’’ and ‘0’ means ‘’LOW’’.

Check the above picture for pin mapping of which port.

Here is the code for turning pin 8 ON and OFF :

void setup() {

Serial.begin(9600);

DDRB |= B00000001; 

/* this replaces pinMode(8,OUTPUT) function and pins 9 to 13 are INPUT here 6th and 7th bits are reserved hence don’t change the values of it */

}

void loop(){

 PORTB |= B11000001;  

/*6th and //7th bits are reserved hence don’t change the //values of it rest all 0’s are LOW and 1 is HIGH(means 8th pin HIGH). */

 delay(3000);

 PORTB &= B11000000;  

/*6th and //7th bits are reserved hence don’t change the //values of it rest all 0’s are LOW (means 8th pin OFF along with up to 13 pin). */

 delay(3000);

 Serial.println(PORTB);
}
 

       
 

for the futher more details check this document