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I'm having problems with using Arduino Leonardo PWM outputs (I'm actually using YUN board).

I need 4 PWM outputs that generally have the same base frequency of around 10 to 20 Hz or so.

I'm using timer 1 (A-pin-9,B-pin-10,C-pin-11) and timer 4 (A-pin-13)

I get pins 9,10,and 13 PWM output working decent, but for some reason pin 11 PWM frequency is much much higher.

Pins 9,10,11 should be working off TIMER 1 which all use the same pre-scaler, so I dont know how 9 and 10 can have one frequency, and 11 have a different frequency.

Here is my code can anybody see anything wrong? thanks!

    #define PWM_4A_PIN  13 
    #define PWM_1C_PIN  11

    #define PWM_1B_PIN  10 
    #define PWM_1A_PIN  9 

    void setup() {
     TCCR1B = TCCR1B & 0b11111000 | 0x05;
     TCCR4B = TCCR1B & 0b11110000 | 0x09;
     analogWrite(PWM_4A_PIN,128);
     analogWrite(PWM_1C_PIN,128);
     analogWrite(PWM_1B_PIN,128);
     analogWrite(PWM_1A_PIN,128);
    }

    void loop() 
    {
    }
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1 Answer 1

up vote 2 down vote

Pins 9,10,11 should be working off TIMER 1 which all use the same pre-scaler, so I dont know how 9 and 10 can have one frequency, and 11 have a different frequency.

Unless D11 is configured as OC0A instead of OC1C, which means that it will work off timer 0.

TCCR0A &= ~(_BV(COM0A1) | _BV(COM0A0));
TCCR1A |= _BV(COM1C1) | _BV(COM1C0);
 ...
OCR1C = ...;
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Thanks Inacio, I tried your code but the same result D11 has much higher freq than 9 and 10, its very strange! –  rough neck Sep 9 '14 at 14:59
    
Did you use analogWrite() on D11? That will reset it to OC0A. –  Ignacio Vazquez-Abrams Sep 9 '14 at 15:04
    
if I replace analogWrite(11,128) with OCR1C=128, then no output at all –  rough neck Sep 9 '14 at 15:16
    
Here is the whole code as it is now#define PWM_4A_PIN 13 #define PWM_1C_PIN 11 #define PWM_1B_PIN 10 #define PWM_1A_PIN 9 void setup() { TCCR1B = TCCR1B & 0b11111000 | 0x05; TCCR4B = TCCR1B & 0b11110000 | 0x09; TCCR0A &= ~(_BV(COM0A1) | _BV(COM0A0)); TCCR3A |= _BV(COM1C1) | _BV(COM1C0); //TCCR0A=0; //TCCR1A=0xb01010101; pinMode(11,OUTPUT); OCR1C=128; analogWrite(PWM_4A_PIN,128); //analogWrite(PWM_1C_PIN,128); analogWrite(PWM_1B_PIN,128); analogWrite(PWM_1A_PIN,128); } void loop() { } –  rough neck Sep 9 '14 at 15:17
    
Call analogWrite() once to configure everything else, then perform the assignments in my answer. –  Ignacio Vazquez-Abrams Sep 9 '14 at 15:20

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