Arduino PWM 1kHz and 10-bit resolution

Question

As the title says, I need 1khz frequency signal with 10-bit resolution. But I am not good with uControllers and complicated programming.

I need a simple code for this task.

I tried using this Interactive PWM from arduinoslovakia.eu but I dont know what the frequency is at 10-bit resolution and how to set frequency in this code.

• Nick Gammon: Are you talking about a square wave? In what way would it have 10-bit resolution? Either it is 1 kHz or not, yes? Are you talking about an error factor? Like, 1 kHz +/- 5% ?
• Majenko: @NickGammon The "10-bit resolution" will refer to the resolution of the duty cycle parameter. i.e., a duty cycle between 0 and 1023 instead of the normal 0 to 255.
• Nick Gammon: Perhaps but the rather brief question does not mention duty cycles.
• Majenko: @NickGammon No, but it does mention PWM, and PWM has a duty cycle (which is what makes it PWM).

Answer 1

I see you are talking about using the 16-bit timer, which is Timer 1 on the Uno.

Assuming you are using a Uno this code will do it:

// Clock frequency divided by 1 kHz frequency desired
const long timer1_OCR1A_Setting = F_CPU / 1000;
const byte outputPin = 10; // Timer 1 "B" output: OC1B
void setup() 
 {
 pinMode (outputPin, OUTPUT);
 // set up Timer 1
 // Fast PWM top at OCR1A
 TCCR1A = bit (WGM10) | bit (WGM11) | bit (COM1B1); // fast PWM, clear OC1B on compare
 TCCR1B = bit (WGM12) | bit (WGM13) | bit (CS10); // fast PWM, no prescaler
 OCR1A = timer1_OCR1A_Setting - 1; // zero relative
 OCR1B = (timer1_OCR1A_Setting / 2) - 1; // 50 % duty cycle
 } // end of setup
void loop()
 {
 }

You can change the 1000 in the calculation for timer1_OCR1A_Setting, within reason, to get other frequencies.

See my page about timers for more background information.

• Gerben: On a 16Mhz Arduino you'd get around 14 bits of resolution, using this code. It is however impossible to get exactly 14-bit (or 10-bit) of resolution without changing the frequency (to around 0.9765kHz).
• Nick Gammon: To explain that comment, OCR1A would be set to 16000 using the above code, and that is log(16000)/log(2) bits, namely 13.97 bits roughly. Therefore your duty cycle (OCR1B) could be in the range 0 to 15999 giving at least 10 bits of resolution.
• Vikas Kumar: Thanks for the answer.