i need to generate a 40KHZ square wave can anybody please provide me the the code for the same because i donot have any idea regarding this, i'm a total beginner in microcontrollers and arduino. and can anyone please tell me if we can generate a sine wave of 40KHz via arduino. please help me its damn urgent.

Sine wave? No. Square wave? Yes. I think you'd have to manually futz with the timer control registers (use a timer other than timer0, so you don't break millis)

You could probably get 40kHz sine with a Due. Why do you think you need a sine?

Why do you think you need a sine? He is probably driving an ultrasonic transmitter and thinks you need a sin wave (which you don't ).

OP is asking for square wave. yes possible time is 1250 microseconds. in the loop current=micros() if (current-old>1250){invert output, old=current}

Generating 40kHz square wave http://forum.arduino.cc/index.php?topic=139918.0 const byte LED = 3; // Timer 2 "B" output: OC2B const long frequency = 40000L; // Hz void setup() { pinMode (LED, OUTPUT); TCCR2A = _BV (WGM20) | _BV (WGM21) | _BV (COM2B1); // fast PWM, clear OC2B on compare TCCR2B = _BV (WGM22) | _BV (CS21); // fast PWM, prescaler of 8 OCR2A = ((F_CPU / 8) / frequency) - 1; // zero relative OCR2B = ((OCR2A + 1) / 2) - 1; // 50% duty cycle } // end of setup void loop() { }

actually my project is a very complicated one i need a 40-60 KHz sine wave with constant current 4mA, my project is IMPEDANCE PLETHYSMOGRAPHY if anyone has heard the name, anyways i can convert square wave into a approx sine wave using caps just to make the squares a bit curvy, please give me the code for 40 KHz PWM, i had tried few of the codes in the previous threads, but they wwere not working.

AWOL: You could probably get 40kHz sine with a Due. Why do you think you need a sine? because i need a sine wave to feed to the disposable electrodes and measure the blood flow by impedance plethysmography i guess i'm right. see i do not have any idea of all this i'm a Production engg student i just don't under why my teachers are making me to do such a rocket science project, but anyways please help me

BillHo: Generating 40kHz square wave Generating 40kHz square wave - Programming Questions - Arduino Forum const byte LED = 3; // Timer 2 "B" output: OC2B const long frequency = 40000L; // Hz void setup() { pinMode (LED, OUTPUT); TCCR2A = _BV (WGM20) | _BV (WGM21) | _BV (COM2B1); // fast PWM, clear OC2B on compare TCCR2B = _BV (WGM22) | _BV (CS21); // fast PWM, prescaler of 8 OCR2A = ((F_CPU / 8) / frequency) - 1; // zero relative OCR2B = ((OCR2A + 1) / 2) - 1; // 50% duty cycle } // end of setup void loop() { } thank you brother i hope this will work

terrorblade: thank you brother i hope this will work sorry but just wanted to ask, which pin will i get the output, i mean as i can see there is nothing inside the void loo(), i mean what should i put inside the void loop()

40KHz pwm square wave

Projects General Guidance

Grumpy_Mike March 2, 2015, 10:04pm 6

Shooter please read the OP message he said:-

and can anyone please tell me if we can generate a sine wave of 40KHz via arduino.

And that code is never going to work.

Please help me !

Topic		Replies	Views
Trying to get audio output from a 1/4 jack using PWM and an RC filter Audio	14	462	September 29, 2025
Square Wave Frequency Pulse Generator General Guidance	23	495	October 6, 2026
Waveform synthesis on the R4 UNO R4 Minima	26	3152	April 9, 2025
Working Due Sine Wave By Frequency (Please help me understand) Programming	28	1037	March 23, 2024
PWM of square wave Programming	14	4969	February 9, 2015

40KHz pwm square wave

Related topics