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added examples for clock and timer
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‎examples/pcf8523_clockout.py

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# SPDX-FileCopyrightText: 2023 Bernhard Bablok
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# SPDX-License-Identifier: MIT
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# Simple demo for clockout-mode (square-wave generation)
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# Note that for 32kHz, the duty-cycle is from 60:40 to 40:60, thus
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# it is not a perfect square wave (see datasheet 8.9.1.2)
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import time
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import board
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import busio
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import countio
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from digitalio import Pull
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from adafruit_pcf8523.clock import Clock
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PIN_SDA = board.GP2 # connect to RTC
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PIN_SCL = board.GP3 # connect to RTC
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# use board.SCL and board.SDA if available
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i2c = busio.I2C(PIN_SCL, PIN_SDA)
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# or i2c = board.I2C() if available
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clock = Clock(i2c)
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# pin must support countio
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PIN_COUT = board.GP5
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counter = countio.Counter(pin=PIN_COUT, edge=countio.Edge.RISE, pull=Pull.UP)
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DURATION = 10
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# Main loop:
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while True:
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# disable clockout
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print(f"testing disabled clock for {DURATION} seconds")
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clock.clockout_frequency = clock.CLOCKOUT_FREQ_DISABLED
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counter.reset()
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time.sleep(DURATION)
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print(f"clock-pulses: {counter.count}")
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print(f"clock-freq: {counter.count/DURATION}")
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# test 32kHz
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print(f"testing 32 kHz clock for {DURATION} seconds")
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clock.clockout_frequency = clock.CLOCKOUT_FREQ_32KHZ
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counter.reset()
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time.sleep(DURATION)
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clock.clockout_frequency = clock.CLOCKOUT_FREQ_DISABLED
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print(f"clock-pulses: {counter.count}")
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print(f"clock-freq: {counter.count/DURATION}")
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# test 4kHz
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print(f"testing 4 kHz clock for {DURATION} seconds")
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clock.clockout_frequency = clock.CLOCKOUT_FREQ_4KHZ
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counter.reset()
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time.sleep(DURATION)
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clock.clockout_frequency = clock.CLOCKOUT_FREQ_DISABLED
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print(f"clock-pulses: {counter.count}")
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print(f"clock-freq: {counter.count/DURATION}")
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# test 1Hz
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print(f"testing 1 Hz clock for {DURATION} seconds")
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clock.clockout_frequency = clock.CLOCKOUT_FREQ_1HZ
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counter.reset()
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time.sleep(DURATION)
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clock.clockout_frequency = clock.CLOCKOUT_FREQ_DISABLED
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print(f"clock-pulses: {counter.count}")
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print(f"clock-freq: {counter.count/DURATION}")

‎examples/pcf8523_timer_flag.py

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# SPDX-FileCopyrightText: 2023 Bernhard Bablok
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# SPDX-License-Identifier: MIT
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# Simple demo for timer operation using the timer-flag
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import board
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LOW_FREQ_TIMER = 10
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HIGH_FREQ_TIMER = 0.02
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HIGH_FREQ_TIME = 10
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PIN_SDA = board.GP2
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PIN_SCL = board.GP3
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# use board.SCL and board.SDA if available
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import time
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import busio
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from adafruit_pcf8523.timer import Timer
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from adafruit_pcf8523.clock import Clock
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i2c = busio.I2C(PIN_SCL, PIN_SDA)
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# or i2c = board.I2C() if available
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timer = Timer(i2c)
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clock = Clock(timer.i2c_device)
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clock.clockout_frequency = clock.CLOCKOUT_FREQ_DISABLED
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# Main loop:
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while True:
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print("low-frequency timer: checking timer-flag")
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timer.timer_enabled = False
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timer.timer_status = False
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timer.timer_frequency = timer.TIMER_FREQ_1HZ
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timer.timer_value = LOW_FREQ_TIMER
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start = time.monotonic()
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timer.timer_enabled = True
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while not timer.timer_status and time.monotonic() - start < LOW_FREQ_TIMER + 1:
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pass
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if not timer.timer_status:
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# shoud not happen!
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print(f"error: timer did not fire within {LOW_FREQ_TIMER+1} seconds!")
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else:
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elapsed = time.monotonic() - start
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print(f"elapsed: {elapsed}")
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print("high-frequency timer: checking timer-flag")
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timer.timer_enabled = False
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timer.timer_status = False
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timer.timer_frequency = timer.TIMER_FREQ_4KHZ
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timer.timer_value = min(round(HIGH_FREQ_TIMER * 4096), 255)
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counter = 0
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start = time.monotonic()
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end = start + HIGH_FREQ_TIME
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timer.timer_enabled = True
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while time.monotonic() < end:
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if not timer.timer_status:
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continue
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timer.timer_status = False
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counter += 1
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if counter > 0:
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mean_interval = (time.monotonic() - start) / counter
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print(f"interval requested: {HIGH_FREQ_TIMER}")
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print(f"interval observed: {mean_interval} (mean of {counter} alarms)")
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else:
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print(f"error: timer did not fire within {HIGH_FREQ_TIME} seconds!")
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print("error: timer did not fire")

‎examples/pcf8523_timer_interrupt.py

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# SPDX-FileCopyrightText: 2023 Bernhard Bablok
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# SPDX-License-Identifier: MIT
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# Simple demo for timer operation, using the interrupt-pin
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import board
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LOW_FREQ_TIMER = 10
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HIGH_FREQ_TIMER = 0.02
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HIGH_FREQ_TIME = 10
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PIN_INT = board.GP5
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PIN_SDA = board.GP2
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PIN_SCL = board.GP3
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# use board.SCL and board.SDA if available
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import time
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import busio
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from digitalio import DigitalInOut, Direction, Pull
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from adafruit_pcf8523.timer import Timer
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from adafruit_pcf8523.clock import Clock
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i2c = busio.I2C(PIN_SCL, PIN_SDA)
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# or i2c = board.I2C() if available
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timer = Timer(i2c)
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clock = Clock(timer.i2c_device)
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clock.clockout_frequency = clock.CLOCKOUT_FREQ_DISABLED
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# interrupt pin
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intpin = DigitalInOut(PIN_INT)
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intpin.direction = Direction.INPUT
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intpin.pull = Pull.UP
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# Main loop:
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timer.pulsed = False
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timer.timer_interrupt = True
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while True:
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print("low-frequency timer: checking interrupt")
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timer.timer_enabled = False
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timer.timer_status = False
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timer.timer_frequency = timer.TIMER_FREQ_1HZ
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timer.timer_value = LOW_FREQ_TIMER
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start = time.monotonic()
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timer.timer_enabled = True
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while intpin.value and time.monotonic() - start < LOW_FREQ_TIMER + 1:
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pass
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if intpin.value:
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# shoud not happen!
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print(f"error: timer did not fire within {LOW_FREQ_TIMER+1} seconds!")
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else:
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elapsed = time.monotonic() - start
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print(f"elapsed: {elapsed}")
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print("high-frequency timer: checking interrupt")
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timer.timer_enabled = False
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timer.timer_status = False
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timer.timer_frequency = timer.TIMER_FREQ_4KHZ
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timer.timer_value = min(round(HIGH_FREQ_TIMER * 4096), 255)
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counter = 0
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start = time.monotonic()
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end = start + HIGH_FREQ_TIME
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timer.timer_enabled = True
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while time.monotonic() < end:
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if intpin.value:
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continue
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timer.timer_status = False
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counter += 1
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if counter > 0:
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mean_interval = (time.monotonic() - start) / counter
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print(f"interval requested: {HIGH_FREQ_TIMER}")
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print(f"interval observed: {mean_interval} (mean of {counter} alarms)")
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else:
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print(f"error: timer did not fire within {HIGH_FREQ_TIME} seconds!")
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print("error: timer did not fire")

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