Beginning Arduino: Control LED

Arduino is quite famous not as a open source hardware. One basic example here:

LED blinking

int led = 13;

void setup() {              
  // initialization
  pinMode(led, OUTPUT);  
}


void loop() {
  digitalWrite(led, HIGH);  
  delay(1000);              
  digitalWrite(led, LOW);  
  delay(1000);              
}

Basically the idea is delay(1000) which is one second and turn the pin led to High/low

If add a user to control this:

int led = 13;

int keyF = 11;  // user button switch ==> faster
int keyS = 12;  // user button switch ==> slower

#define MAX_SELECT 4
int tperiod[MAX_SELECT] = {1000, 500, 250, 125};  // blink rates: 1/2sec,1/sec,2/sec,4/sec
int tselect;

void setup() {              
  // initialize the digital pin as an output.
  pinMode(led, OUTPUT);  
  pinMode(keyF, INPUT);
  pinMode(keyS, INPUT);
  tselect = 1;    
}


void loop() {
  if (ledState == HIGH)
    ledState = LOW;          
  else
    ledState = HIGH;          
  digitalWrite(led,ledState);

  delay(1000);                

  if (readUserKeyF()) tselect = blinkFaster();
  if (readUserKeyS()) tselect = blinkSlower();
}

int blinkFaster(void) {
  if (tselect < MAX_SELECT-1)
    return (tselect+1);
  else
    return tselect;
}
int blinkSlower(void) {
  if (tselect > 0)
    return (tselect - 1);
  else
    return tselect;
}

int readUserKeyF(void) {
  if (digitalRead(keyF) == LOW) return 1;
  else return 0;
}
int readUserKeyS(void) {
  if (digitalRead(keyS) == LOW) return 1;
  else return 0;
}
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