I am making a POV (persistance of vision) project using atmega8 ,which is being programmed by arduino (uno) as ISP i am following this tutorial videos and blink led code is working well for me as in the video, I tired the same code by changing the delay for verifying whether the circuit works properly and i was working nice But i uploaded my persistance of vision code(POV) its no working none of the leds is blinking I using the correct pin i verified it with arduino uno atmega8 pin mapping Here is my Persistance of vision code int _[] = {0,0,0,0,0, 0,0,0,0,0, 0,0,0,0,0}; int A[] = {0,1,1,1,1, 1,0,1,0,0, 0,1,1,1,1}; int B[] = {1,1,1,1,1, 1,0,1,0,1, 0,1,0,1,0}; int C[] = {0,1,1,1,0, 1,0,0,0,1, 1,0,0,0,1}; int D[] = {1,1,1,1,1, 1,0,0,0,1, 0,1,1,1,0}; int E[] = {1,1,1,1,1, 1,0,1,0,1, 1,0,1,0,1}; int F[] = {1,1,1,1,1, 1,0,1,0,0, 1,0,1,0,0}; int G[] = {0,1,1,1,0, 1,0,1,0,1, 0,0,1,1,0}; int H[] = {1,1,1,1,1, 0,0,1,0,0, 1,1,1,1,1}; int I[] = {0,0,0,0,1, 1,0,1,1,1, 0,0,0,0,1}; int J[] = {1,0,0,0,0, 1,0,0,0,1, 1,1,1,1,1}; int K[] = {1,1,1,1,1, 0,0,1,0,0, 0,1,0,1,1}; int L[] = {1,1,1,1,1, 0,0,0,0,1, 0,0,0,0,1}; int M[] = {1,1,1,1,1, 0,1,1,0,0, 0,1,1,1,1}; int N[] = {1,1,1,1,1, 1,0,0,0,0, 0,1,1,1,1}; int O[] = {0,1,1,1,0, 1,0,0,0,1, 0,1,1,1,0}; int P[] = {1,1,1,1,1, 1,0,1,0,0, 0,1,0,0,0}; int Q[] = {0,1,1,1,1, 1,0,0,1,1, 0,1,1,1,1}; int R[] = {1,1,1,1,1, 1,0,1,0,0, 0,1,0,1,1}; int S[] = {0,1,0,0,1, 1,0,1,0,1, 1,0,0,1,0}; int T[] = {1,0,0,0,0, 1,1,1,1,1, 1,0,0,0,0}; int U[] = {1,1,1,1,1, 0,0,0,0,1, 1,1,1,1,1}; int V[] = {1,1,1,1,0, 0,0,0,0,1, 1,1,1,1,0}; int W[] = {1,1,1,1,0, 0,0,1,1,0, 1,1,1,1,0}; int X[] = {1,1,0,1,1, 0,0,1,0,0, 1,1,0,1,1}; int Y[] = {1,1,0,0,0, 0,0,1,0,0, 1,1,1,1,1}; int Z[] = {1,0,0,1,1, 1,0,1,0,1, 1,1,0,0,1}; int letterSpace; int dotTime; void setup() { // setting the ports of the leds to OUTPUT pinMode(9, OUTPUT); pinMode(10, OUTPUT); pinMode(11, OUTPUT); pinMode(12, OUTPUT); pinMode(13, OUTPUT); // defining the space between the letters (ms) letterSpace = 6; // defining the time dots appear (ms) dotTime = 3; } void printLetter(int letter[]) { int y; // printing the first y row of the letter for (y=0; y<5; y++) { digitalWrite(y+2, letter[y]); } delay(dotTime); // printing the second y row of the letter for (y=0; y<5; y++) { digitalWrite(y+2, letter[y+5]); } delay(dotTime); // printing the third y row of the letter for (y=0; y<5; y++) { digitalWrite(y+2, letter[y+10]); } delay(dotTime); // printing the sspace between the letters for (y=0; y<5; y++) { digitalWrite(y+2, 0); } delay(letterSpace); } void loop() { // you can print your own text by modifing here :) printLetter(H); printLetter(E); printLetter(L); printLetter(L); printLetter(O); printLetter(_); }