Bar Graph Toggle From Keyboard

/*

Bar Graph Toggle From Keyboard

*/

int c;

void setup() {

Serial.begin(9600);

pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
pinMode(7, OUTPUT);
pinMode(8, OUTPUT);
pinMode(9, OUTPUT);
pinMode(10, OUTPUT);

digitalWrite( 3, HIGH);
digitalWrite( 4, HIGH);
digitalWrite( 5, HIGH);
digitalWrite( 6, HIGH);
digitalWrite( 7, HIGH);
digitalWrite( 8, HIGH);
digitalWrite( 9, HIGH);
digitalWrite(10, HIGH);

}


void loop() {


if (Serial.available()) {

c = Serial.read();

if (c >= '1' && c <= '8') {

c = c & 0x0f; // Convert ascii to int
c += 2; // pins 3-10 == keys 1-8

digitalWrite(c, !digitalRead(c)); // Toggle pin
}
}
}

setterm -blank

"setterm -blank nn will tell the console driver to blank the screen after nn minutes of inactivity. (With nn = 0, screensaving is turned off. In some old kernels this first took effect after the next keyboard interrupt.) -- Linux Keyboard and Console HOWTO

Arduino as a clock source

Arduino as a 1MHz clock...

/* 1MHz Clock */

int ledPin = 7;

void setup() {
pinMode(ledPin, OUTPUT);
noInterrupts();
}

void loop() {
PORTD ^= 10000000;
asm("NOP");
asm("NOP");
asm("NOP");
}

Fastest Arduino (16MHz) output: 1.6MHz