Hi,
any pointers on what method should i be looking at if i want to multiply externally a PWM signal frequency from the arduino?
I'm basically looking for the simplest, most robust way since i'll be dealing with +10A currents.
Thanks
Why would you want to frequency multiply a PWM signal?
What are you trying to actually do? The Arduino PWM hardware is
more flexible than you think, though you may have to override
default settings.
I'd like to reach the MHz level. I read somewhere that a guy got it running to 4 MHz, which is actually far more than i need, but i'm a bit weary of editing the Arduino.
I'm doing an experiment with a mosfet to see how it would operate under such frequencies and a fair amount of current.
My first thought was to just multiply the output of the arduino externally, but i'm open to ideas.
HCMOS NOR gate with signal in to one input, same signal through the other three gates in cascade plus or minus an RC delay, to the other input.
Duty cycle not 50%, adjust components according to frequency in use.
Paul__B:
HCMOS NOR gate with signal in to one input, same signal through the other three gates in cascade plus or minus an RC delay, to the other input.Duty cycle not 50%, adjust components according to frequency in use.
Thanks, i'll definitely check it out.
far_1:
I'd like to reach the MHz level. I read somewhere that a guy got it running to 4 MHz, which is actually far more than i need, but i'm a bit weary of editing the Arduino.I'm doing an experiment with a mosfet to see how it would operate under such frequencies and a fair amount of current.
My first thought was to just multiply the output of the arduino externally, but i'm open to ideas.
So you don't want to multiply frequency, you want a high frequency PWM in the first place?
What resolution at 4MHz? Which MOSFETs are you looking at because for that frequency
you seem to be in the realm of gallium nitride or silicon-germanium or other exotic tech?
To see how a MOSFET behaves during switching you don't need a high frequency signal,
you do need a digital storage oscilloscope.
Well, we could say that yes. A high frequency 50% (+/-) duty cycle PWM that could reach 1 MHz.
Low resolution from what i can tell...not exactly sure how much.
As for the mosfet...not decided yet, but most certainly something with an appropriate switching time. 0.5MHz would also be nice though.
You can clock Arduino timers upto 16MHz, so you can get 4 bit PWM at 1MHz, 3 bit
at 2MHz, etc. You program the timer prescaler to divide-by-1 and use a mode where
the ICR register sets the period.
The ATTiny85 has a unique 64MHz internal PLL that can produce faster PWM than the other Atmel chips. The relevant datasheet page is 94, section 12.3.9, PLLCSR register. I believe that the 64MHz clock source can still be prescaled with the usual TCCR1.
In theory, anyway. No idea if/how that all actually works.