Hello,
I am currently working from some Python3 source I found years ago from Mark Yoder. Here is the breakdown of the changes I made…w/out importing glob w/ its use in play:
#!/usr/bin/python3
import pathlib
from time import sleep
class PWM:
def start(duty, freq=2000, polarity=0):
""" Set up and start the PWM channel. """
path = pathlib.Path("/dev/bone/pwm/1/b")
if path == None:
return None
period_ns = 1e9 / freq
duty_ns = (period_ns * (duty / 100.0))
# export
try:
fd = open(path + "/export", 'w')
fd.write(str(path))
fd.close()
except:
pass
time.sleep(0.05) # Give export a chance
# Duty Cycle - Set to 0 so period can be changed
try:
fd = open(pathpwm + "/duty_cycle", 'w')
fd.write('0')
fd.close()
except:
pass
# Period
fd = open(pathpwm + "/period", 'w')
fd.write(str(int(period_ns)))
fd.close()
# Duty Cycle
fd = open(pathpwm + "/duty_cycle", 'w')
fd.write(str(int(duty_ns)))
fd.close()
# Enable
fd = open(pathpwm + "/enable", 'w')
fd.write('1')
fd.close()
return 'Started'
def set_frequency(freq):
""" Change the frequency
frequency - frequency in Hz (freq > 0.0) """
path = Path("/dev/bone/pwm/1")
pathpwm = path + "/b"
# compute current duty cycle
fd = open(pathpwm + "/duty_cycle", 'r')
duty_cycle_ns = int(fd.read())
fd.close()
fd = open(pathpwm + "/period", 'r')
period_ns = int(fd.read())
fd.close()
duty_cycle = duty_cycle_ns/period_ns # compute current duty cycle as fraction
period_ns = 1e9 / freq # compute new period
duty_cycle_ns = period_ns*duty_cycle # compute new duty cycle as fraction of period
# print('duty_cycle: ' + str(duty_cycle))
# print('period_ns: ' + str(period_ns))
# print('duty_cycle_ns: ' + str(duty_cycle_ns))
# Duty Cycle - Set to 0
fd = open(pathpwm + "/duty_cycle", 'w')
fd.write('0')
fd.close()
# Period
fd = open(pathpwm + "/period", 'w')
fd.write(str(int(period_ns)))
fd.close()
# Duty Cycle
fd = open(pathpwm + "/duty_cycle", 'w')
fd.write(str(int(duty_cycle_ns)))
fd.close()
def set_duty_cycle(duty):
""" Change the duty cycle.
dutycycle - between 0.0 and 100.0 """
path = get_pwm_path()
pathpwm = path + "/b"
fd = open(pathpwm + "/period", 'r')
period_ns = int(fd.read())
fd.close()
duty_cycle_ns = duty/100 * period_ns
# Duty Cycle
fd = open(pathpwm + "/duty_cycle", 'w')
fd.write(str(int(duty_cycle_ns)))
fd.close()
def stop():
""" Stop the PWM channel. """
path = pwm_path()
pathpwm = path + "/b"
# Disable
fd = open(pathpwm + "/enable", 'w')
fd.write('0')
fd.close()
# unexport
fd = open(path + "/unexport", 'w')
fd.write(str(path[1]))
fd.close()
I am currently working w/ an updated, Bullseye image and kernel 5.10.x. I am seemingly getting the above source to run w/out error. This is the good news.
Currently though, I am running some source outside of this small file to call this file into it for use.
Both files work but do not light my LED via PWM. Anyway, I cannot remember exactly where in the www I got the file but I know it is from Mr. Yoder.
Seth
P.S. If you or anyone you know may be able to point me in the correct direction, please let me know. I tried config-pin p9.16 pwm and this is not the issue. GPIO works! Oh and I am using a BBB Rev. C.
My other file looks similar to this…
import MyOtherFile
from time import sleep
while True:
ration = int(input("Enter Your Favorite Number...: ")
if ration == 0:
PWM.start = 0
PWM.set_frequency = 50
PWM.set_duty_cycle = 75
sleep(5)
else:
pass
I am starting small here and getting setbacks. There is more to the source but I have removed the other glob portions in the first file and removed other functions that glob was using to get file access.