kopia lustrzana https://github.com/micropython/micropython
171 wiersze
5.3 KiB
ReStructuredText
171 wiersze
5.3 KiB
ReStructuredText
:mod:`machine` --- functions related to the hardware
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====================================================
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.. module:: machine
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:synopsis: functions related to the hardware
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The ``machine`` module contains specific functions related to the hardware
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on a particular board. Most functions in this module allow to achieve direct
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and unrestricted access to and control of hardware blocks on a system
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(like CPU, timers, buses, etc.). Used incorrectly, this can lead to
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malfunction, lockups, crashes of your board, and in extreme cases, hardware
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damage.
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.. _machine_callbacks:
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A note of callbacks used by functions and class methods of ``machine`` module:
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all these callbacks should be considered as executing in an interrupt context.
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This is true for both physical devices with IDs >= 0 and "virtual" devices
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with negative IDs like -1 (these "virtual" devices are still thin shims on
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top of real hardware and real hardware intrerrupts). See :ref:`isr_rules`.
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Reset related functions
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-----------------------
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.. function:: reset()
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Resets the device in a manner similar to pushing the external RESET
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button.
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.. function:: reset_cause()
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Get the reset cause. See :ref:`constants <machine_constants>` for the possible return values.
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Interrupt related functions
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---------------------------
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.. function:: disable_irq()
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Disable interrupt requests.
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Returns the previous IRQ state which should be considered an opaque value.
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This return value should be passed to the ``enable_irq`` function to restore
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interrupts to their original state, before ``disable_irq`` was called.
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.. function:: enable_irq(state)
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Re-enable interrupt requests.
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The ``state`` parameter should be the value that was returned from the most
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recent call to the ``disable_irq`` function.
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Power related functions
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-----------------------
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.. function:: freq()
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.. only:: not port_wipy
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Returns CPU frequency in hertz.
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.. only:: port_wipy
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Returns a tuple of clock frequencies: ``(sysclk,)``
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These correspond to:
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- sysclk: frequency of the CPU
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.. function:: idle()
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Gates the clock to the CPU, useful to reduce power consumption at any time during
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short or long periods. Peripherals continue working and execution resumes as soon
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as any interrupt is triggered (on many ports this includes system timer
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interrupt occurring at regular intervals on the order of millisecond).
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.. function:: sleep()
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Stops the CPU and disables all peripherals except for WLAN. Execution is resumed from
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the point where the sleep was requested. For wake up to actually happen, wake sources
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should be configured first.
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.. function:: deepsleep()
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Stops the CPU and all peripherals (including networking interfaces, if any). Execution
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is resumed from the main script, just as with a reset. The reset cause can be checked
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to know that we are coming from ``machine.DEEPSLEEP``. For wake up to actually happen,
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wake sources should be configured first, like ``Pin`` change or ``RTC`` timeout.
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.. only:: port_wipy
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.. function:: wake_reason()
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Get the wake reason. See :ref:`constants <machine_constants>` for the possible return values.
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Miscellaneous functions
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-----------------------
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.. only:: port_wipy
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.. function:: main(filename)
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Set the filename of the main script to run after boot.py is finished. If
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this function is not called then the default file main.py will be executed.
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It only makes sense to call this function from within boot.py.
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.. function:: rng()
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Return a 24-bit software generated random number.
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.. function:: unique_id()
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Returns a byte string with a unique identifier of a board/SoC. It will vary
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from a board/SoC instance to another, if underlying hardware allows. Length
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varies by hardware (so use substring of a full value if you expect a short
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ID). In some MicroPython ports, ID corresponds to the network MAC address.
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.. function:: time_pulse_us(pin, pulse_level, timeout_us=1000000)
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Time a pulse on the given `pin`, and return the duration of the pulse in
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microseconds. The `pulse_level` argument should be 0 to time a low pulse
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or 1 to time a high pulse.
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If the current input value of the pin is different to `pulse_level`,
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the function first (*) waits until the pin input becomes equal to `pulse_level`,
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then (**) times the duration that the pin is equal to `pulse_level`.
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If the pin is already equal to `pulse_level` then timing starts straight away.
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The function will return -2 if there was timeout waiting for condition marked
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(*) above, and -1 if there was timeout during the main measurement, marked (**)
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above. The timeout is the same for both cases and given by `timeout_us` (which
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is in microseconds).
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.. _machine_constants:
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Constants
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---------
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.. data:: machine.IDLE
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.. data:: machine.SLEEP
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.. data:: machine.DEEPSLEEP
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irq wake values
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.. data:: machine.PWRON_RESET
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.. data:: machine.HARD_RESET
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.. data:: machine.WDT_RESET
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.. data:: machine.DEEPSLEEP_RESET
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.. data:: machine.SOFT_RESET
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reset causes
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.. data:: machine.WLAN_WAKE
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.. data:: machine.PIN_WAKE
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.. data:: machine.RTC_WAKE
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wake reasons
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Classes
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-------
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.. toctree::
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:maxdepth: 1
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machine.ADC.rst
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machine.I2C.rst
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machine.Pin.rst
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machine.RTC.rst
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machine.SD.rst
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machine.SPI.rst
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machine.Timer.rst
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machine.UART.rst
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machine.WDT.rst
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