def main():
# setup wiringpi
if wipi.wiringPiSetup():
print("Failing to setup wiringPi")
sys.exit()
# wPi Port 24 corresponds to Phys Pin 35
PWM_PORT = 24
# parameters to compute frequency
RANGE = 480
DIVISOR = 2
# duty cycle percentage
PERCENTAGE_DUTY_CYCLE = 40
# duty_cycle = ( range * duty_cycle(%) ) / 100
DUTY_CYCLE = (RANGE * PERCENTAGE_DUTY_CYCLE) / 100
#*** setting PWM parameters **
# sets port to ALT MODE-5
FSEL_ALT5 = 0b010
wipi.pinModeAlt(PWM_PORT, FSEL_ALT5)
# sets Mark/Space mode
wipi.pwmSetMode(wipi.GPIO.PWM_MODE_MS)
# frequency = 19.2e6 / ( DIVISOR x RANGE )
wipi.pwmSetRange(RANGE)
wipi.pwmSetClock(DIVISOR)
#***
# generates PWM at a determined duty cycle
wipi.pwmWrite(PWM_PORT, DUTY_CYCLE)
F_BASE = 19.2e6
FREQUENCY_OUT = F_BASE / (RANGE * DIVISOR)
print("PWM output pin: 35")
print("PWM frequency: {} Hz".format(FREQUENCY_OUT))
print("PWM duty cycle: {}".format((DUTY_CYCLE * 100) / RANGE))
c = raw_input("To finish, press \'Enter\'")
# turns off pwm output
wipi.pwmWrite(PWM_PORT, 0)
def read_ATR(serial):
wiringpi.pinMode(TX, INPUT)
wiringpi.pullUpDnControl(TX, PUD_UP)
first = wiringpi.millis()
data_str = ''
while (wiringpi.millis() - first) < 100:
if wiringpi.serialDataAvail(serial) > 0:
first = wiringpi.millis()
data = wiringpi.serialGetchar(serial)
if (data < 16):
data *= 16
data_str += ('{:02x}'.format(data)) + ' '
wiringpi.pullUpDnControl(TX, PUD_OFF)
wiringpi.pinModeAlt(TX, 4)
data_str = data_str.lstrip('00')
return data_str
def read_response(serial, ser, length):
wiringpi.pinMode(TX, INPUT)
wiringpi.pullUpDnControl(TX, PUD_UP)
first = wiringpi.millis()
wiringpi.delay(50)
## Save all the data from RX excluding bounced data
data_list = []
num_ser = wiringpi.serialDataAvail(serial)
while (wiringpi.millis() - first) < 100:
if wiringpi.serialDataAvail(serial) > 0:
first = wiringpi.millis()
data = wiringpi.serialGetchar(serial)
if (wiringpi.serialDataAvail(serial) < (num_ser - length)):
data_list.append('{:02x}'.format(data))
wiringpi.pullUpDnControl(TX, PUD_OFF)
wiringpi.pinModeAlt(TX, 4)
return data_list
def __restore_gpio_pins__(self):
""" Restore HW I2C functionality on GPIO pins 2 & 3 """
wiringpi.pinModeAlt(3, 4) # restore ALT0 functionality on SCL pin
wiringpi.pinModeAlt(2, 4) # restore ALT0 functionality on SDA pin
self.BusActive = False