Yes. The counter part of it works exactly like it does in the PWM case - in fact you could have a PWM output from the A channel, driven from clock input on the B channel if you really wanted to, but that's not the common use case.Your calls to set the limit and level aren't wrong, but I suspect you don't need them for your use-case.
Those would be for the counter so it has an auto reset?
So if you are just counting input pulses - for an event counter, or to measure frequency, then you normally leave the wrap at the default (64K-1) so the 16-bit counter wraps round, and if you haven't enabled the A output then the level value doesn't do anything so you don't need to set it.
You might want to set the counter to count down for some applications, default is to count up.
Yes. So if you are just counting pulses that come in at a reasonable rate, you want a divider of 1. If you are trying to measure the frequency of a clock in the hundreds-of-kilohertz to megahertz range, then you need a divider to make the counts reasonable.What about the clock divider? I have 8 but does that mean it takes 8 pulses before the count will increment?
That's exactly how I use it in a clock frequency measuring application. The 4-line chunk of initialisation code I posted earlier is the whole of my initialisation (you don't need the pwm_set_enabled(), pwm_init() will do it for you), and then in my timer function I just have:I've got a timer running that will store and reset the count.
Code:
clock_hz = pwm_get_counter(pwm_gpio_to_slice_num(MY_PIN)) * MY_CLKDIV; pwm_set_counter(pwm_gpio_to_slice_num(MY_PIN), 0);The RP2040 PWM unit is very nice for PWM output, does pulse counting/frequency measuring quite satisfactorily on the B inputs only, but the one thing it doesn't do compared to other similar chips is timer capture - if you need that, you have to implement it in PIO (which is quite easy to do).
Statistics: Posted by arg001 — Sat May 04, 2024 8:22 pm