Can anybody explain me, why the PWM doesn't work in such a simple example?
Generally, Timer interrupt is being called once per 100 ms and then in the interrupt function the bool flag (state ) is being set. Then in the main loop the flag is checked and when it is 1 (true) several instructions are being executed. Next, PWM is generated and measured via ADC and also displayed on the LCD.
The problem is that the PWM is generated as 0 or sligthly over the 0, even when the value put to the analogWrite is 255 (max of 8 bit). Variable counter is incremented without problems and this value is being put to the analogWrite and despite it the PWM doesn't work.
I don't know, totally, what can be wrong.
Can anybody help me?
#include<LiquidCrystal.h>
#include<TimerOne.h>
LiquidCrystal lcd(52, 50, 48, 46, 44, 42, 40);
int out = 12;
int in = A7;
volatile bool state;
int counter = 0;
volatile int y;
void setup()
{
lcd.begin(16, 2);
lcd.clear();
pinMode(out, OUTPUT);
pinMode(in, INPUT);
analogReference(DEFAULT);
Timer1.initialize(100000);
Timer1.attachInterrupt(functionInterrupt);
state = 0;
y = 0;
}
void loop()
{
y = analogRead(in);
y = y / 4;
y = y - 128;
if (state === 1)
{
state = 0;
counter++;
if (counter > 255)
//counter = 0;
counter = 200;
//state = 0;
}
analogWrite(out,counter);
lcd.home();
lcd.setCursor(0, 1);
lcd.print(counter);
lcd.setCursor(12,1);
lcd.print(y);
}
void functionInterrupt()
{
state = 1;
}