Code: Select all
from machine import Pin, disable_irq, enable_irq
import micropython
from utime import sleep
def isr(p):
state = disable_irq()
pin_state = p.value()
if pin_state != p.value(): # XXX - I'm reading the value of the pin immediately, and a large percentage of the time the value is different
print("<Boo>", end="")
enable_irq(state)
def main():
micropython.alloc_emergency_exception_buf(100)
sensor = Pin(25, Pin.IN)
sensor.irq(trigger=Pin.IRQ_RISING | Pin.IRQ_FALLING, handler=isr)
while True:
sleep(1)
print(".", end="")
if __name__ == "__main__":
main()
Am I asking too much to use MicroPython to measure how long a digital pin is held HIGH/LOW? A very simplified version of what I'm trying to do is below (error-handling and other biz-logic removed).
Code: Select all
import array
from machine import Pin
import micropython
from utime import sleep, ticks_us, ticks_diff
NUM_VALUES = 128
data_to_process = False
prev_time = ticks_us()
values = array.array('i', (0 for _ in range(NUM_VALUES)))
value_idx = 0
def isr(p):
global data_to_process, prev_time, values, value_idx
curr_time = ticks_us()
# Only capture new data if we've processed the old data
if not data_to_process
len = ticks_diff(curr_time, prev_time)
# Capture if the value was HIGH/LOW
if p.value() == 0:
len *= -1
# There's a bit more biz-logic here, but it's pretty simple (comparisons)
values[value_idx] = len
value_idx += 1
if value_idx == NUM_VALUES:
data_to_process = True
prev_time = curr_time
def process():
global data_to_process, values, value_idx
if not data_to_process:
return
# Will be smarter in the real code
for i in range(len(values)):
print("c[{}]={}".format(i, values[i]))
print("")
# Reset the data so we can capture more!
value_idx = 0
data_to_process = False
def main():
micropython.alloc_emergency_exception_buf(100)
sensor = Pin(25, Pin.IN)
sensor.irq(trigger=Pin.IRQ_RISING | Pin.IRQ_FALLING, handler=isr)
while True:
sleep(1)
process()
if __name__ == "__main__":
main()
