![]() const unsigned TOP = 9999 // With 16 MHz clock and prescale 8 this gives FastPWM at 200 Hz. I put this in an Arduino UNO and my multimeter says that Pin 9 and Pin 10 are producing 199.93 Hz. Using 0x52 changes the Output Compare Mode so there is no PWM on OC1B and OC1A produces a 100 Hz square wave. Looks like you had it right with TCCR1A = 0xA2. The default frequency of the PWM signal is 500 Hz. OCR1B = 5000 // About mid range PWM on pin OC1B Of course the Servo library is an even better idea as it can drive more pins and isnt limited to the PWM-capable pins. Writes an analog value to a pin as a digital PWM (pulse-width modulated) signal. OCR1A = 5000 // About mid range PWM on pin OC1A Pins 2 and 7 have no PWM at the Arduino Zero. TIFR1 = 0 // Timer/Counter1 Interrupt Flag Register TIMSK1 = 0 // Timer/Counter1 Interrupt Mask Register TCCR1B = 0 // Timer/Counter1 Control Register B TCCR1A = 0 // Timer/Counter1 Control Register A There are two types of analog output available on CircuitPython hardware: true analog and PWM (as on Arduino). ![]() This is an integer equal to the ratio of the default timer divider and the new one set (for PWM acceleration). For PWM output on channel B we turn on the following Compare Output Mode bits:Ĭonst unsigned TOP = 9999 // With 16 MHz clock and prescale 8 this gives FastPWM at 200 Hz. The most important thing is CORRECTCLOCK. ![]() For PWM output on channel A we turn on the following Compare Output Mode bits: For Prescale = 8 we turn on the following Clock Select bits: For FastPWM Mode 14 we turn on the following Waveform Generation Mode bits: giving you oodles of resolution (more than you need, but who cares?), so you'd then, in loop, read the pot voltage with analogRead, map() that, which ranges from 0~1023 (assuming the pot is connected the usual way, so wiper voltage goes from 0 to 5v across the range of the pot) to 7800~2900, and to 2200~7100 for OCR1A and OCR1B, giving you the two PWM outputs. With a prescaler of 8, you could set ICR1 to 10000. analogWrite can vary by the type of output used. TCCR1A and TCCR1B for WGM14 (ie WGM10=0, WGM11/12/13=1), then figure out a combination of prescalar (CS10, CS11, CS12 bits) and ICR1 that will get you 200hz (200hz = 0.005 seconds = 5000 microseconds = 80000 clock cycles. 8 Answers Sorted by: 18 +100 digitalWrite will set the specified pin to one of two states - HIGH/LOW, which equate to 5v (3.3v on some boards) and ground respectively. ![]() And since TOP is being configured to a value other than 255, you can't use analogWrite - you need to write your own function to update OCR1A and OCR1B. So that means he needs the WGM where ICR sets TOP, which is only available on Timer1. Doing this will require a WGM where TOP is set by ICR or OCRA, but OCRA would take up one of the output compare channels, and he needs two PWM outputs. The only part of this that's not trivial is that he needs it at 200hz, so he'll need to reconfigure a timer to give 200hz pwm. ![]()
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