pulses_get holding buffer values?

[pycom9]

I am reading a frequency input using pulses_get. When pulses_get is called the first time, it reads 128 values and calculates the frequency correctly. However, when I change the input frequency, the next time pulses_get is called it reads values that are from the previous frequency. I call pulses_get the 3rd time and it reads the NEW frequency correctly. Is there a buffer my program should be clearing? What am I missing? Any help would be much appreciated!

Here is my code:

#setup imports
from machine import Pin
from pycom import pulses_get
import time

p_in        = Pin('P13', mode=Pin.IN)
p_out_pwr   = Pin('P4', mode=Pin.OUT)

#turn on sensor
p_out_pwr(True)
time.sleep(2)

pulses = pulses_get(p_in, 500)

#turn off sensor
p_out_pwr(False)

#print length of pulses tuple
print("Number of pulses: {}".format(len(pulses)))

for i, (level, duration) in enumerate(pulses):
    #calculate pulse ON and OFF time
    if level == 1:
        pulse_on_time = duration
    elif level == 0:
        pulse_off_time = duration 

    if pulse_on_time > 0 and pulse_off_time > 0:
        period = pulse_on_time + pulse_off_time 
        frequency = 1000000.0/period #Hz
        print("i = {:2} f: {} Hz {} khz".format(i, frequency, frequency*.001))```

[kjm]

Does pulses_get clear the pulses dict each time you call it? If not & you are appending into the dict then there is a chance that the pulses dict is still holding old values. Dicts written to in a function, unlike variables, are persistent between calls to the function.

[robert-hh]

@pycom9 pycom.pulses_get() has no means of managing what it is doing. It uses the RMT device. So you could try to use the RMT module API, allowing to deinit and init the channel again. That may reset the internal ringbuffer of the RMT peripheral.