InaMORAta: Difference between revisions

@@ Line 19: / Line 19: @@
 ==Control (PWM)==
-We set up a 25K PWM signal on digital output pin 9. We can't use the standard Arduino PWM system, which operates at lower frequencies (490Hz and 980Hz). We operate directly on timer registers:
+We set up a 25K PWM signal on pin 8. We can't use the standard Arduino PWM system, which operates at lower frequencies (490Hz and 980Hz). We operate directly on timer registers, using timer 4:
 <pre>
    const word PWM_FREQ_HZ = 25000;
-   TCCR1A = 0;
+   TCCR4A = 0;
-   TCCR1B = 0;
+   TCCR4B = 0;
-   TCNT1  = 0;
+   TCNT4  = 0;
-   TCCR1A |= (1 << COM1A1) | (1 << WGM11);
+   ICR4 = (F_CPU / PWM_FREQ_HZ) / 2;
-   TCCR1B |= (1 << WGM13) | (1 << CS10);
+  TCCR4A |= (1 << COM4A1) | (1 << WGM41);
-  ICR1 = 16000000 / (2 * PWM_FREQ_HZ);
+   TCCR4B |= (1 << WGM43) | (1 << CS40);
 </pre>
-This <tt>ICR1</tt> value comes out to 320. We can then set the desired PWM <tt>duty</tt> (0–100) with:
+This <tt>ICR4</tt> value comes out to 320. We can then set the desired PWM <tt>duty</tt> (0–255) with:
 <pre>
-   OCR1A = (word)(duty * 320) / 100
+   OCR4C = duty;
 </pre>