kopia lustrzana https://github.com/micropython/micropython
158 wiersze
6.0 KiB
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158 wiersze
6.0 KiB
ReStructuredText
.. _zephyr_quickref:
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Quick reference for the Zephyr port
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===================================
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Below is a quick reference for the Zephyr port. If it is your first time working with this port please consider reading the following sections first:
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.. toctree::
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:maxdepth: 1
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general.rst
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tutorial/index.rst
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Running MicroPython
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-------------------
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See the corresponding section of the tutorial: :ref:`intro`.
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Delay and timing
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----------------
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Use the :mod:`time <time>` module::
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import time
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time.sleep(1) # sleep for 1 second
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time.sleep_ms(500) # sleep for 500 milliseconds
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time.sleep_us(10) # sleep for 10 microseconds
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start = time.ticks_ms() # get millisecond counter
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delta = time.ticks_diff(time.ticks_ms(), start) # compute time difference
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Pins and GPIO
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-------------
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Use the :ref:`machine.Pin <machine.Pin>` class::
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from machine import Pin
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pin = Pin(("GPIO_1", 21), Pin.IN) # create input pin on GPIO1
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print(pin) # print pin port and number
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pin.init(Pin.OUT, Pin.PULL_UP, value=1) # reinitialize pin
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pin.value(1) # set pin to high
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pin.value(0) # set pin to low
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pin.on() # set pin to high
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pin.off() # set pin to low
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pin = Pin(("GPIO_1", 21), Pin.IN) # create input pin on GPIO1
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pin = Pin(("GPIO_1", 21), Pin.OUT, value=1) # set pin high on creation
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pin = Pin(("GPIO_1", 21), Pin.IN, Pin.PULL_UP) # enable internal pull-up resistor
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switch = Pin(("GPIO_2", 6), Pin.IN) # create input pin for a switch
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switch.irq(lambda t: print("SW2 changed")) # enable an interrupt when switch state is changed
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Hardware I2C bus
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----------------
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Hardware I2C is accessed via the :ref:`machine.I2C <machine.I2C>` class::
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from machine import I2C
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i2c = I2C("I2C_0") # construct an i2c bus
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print(i2c) # print device name
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i2c.scan() # scan the device for available I2C slaves
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i2c.readfrom(0x1D, 4) # read 4 bytes from slave 0x1D
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i2c.readfrom_mem(0x1D, 0x0D, 1) # read 1 byte from slave 0x1D at slave memory 0x0D
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i2c.writeto(0x1D, b'abcd') # write to slave with address 0x1D
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i2c.writeto_mem(0x1D, 0x0D, b'ab') # write to slave 0x1D at slave memory 0x0D
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buf = bytearray(8) # create buffer of size 8
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i2c.writeto(0x1D, b'abcd') # write buf to slave 0x1D
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Hardware SPI bus
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----------------
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Hardware SPI is accessed via the :ref:`machine.SPI <machine.SPI>` class::
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from machine import SPI
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spi = SPI("SPI_0") # construct a spi bus with default configuration
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spi.init(baudrate=100000, polarity=0, phase=0, bits=8, firstbit=SPI.MSB) # set configuration
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# equivalently, construct spi bus and set configuration at the same time
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spi = SPI("SPI_0", baudrate=100000, polarity=0, phase=0, bits=8, firstbit=SPI.MSB)
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print(spi) # print device name and bus configuration
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spi.read(4) # read 4 bytes on MISO
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spi.read(4, write=0xF) # read 4 bytes while writing 0xF on MOSI
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buf = bytearray(8) # create a buffer of size 8
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spi.readinto(buf) # read into the buffer (reads number of bytes equal to the buffer size)
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spi.readinto(buf, 0xF) # read into the buffer while writing 0xF on MOSI
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spi.write(b'abcd') # write 4 bytes on MOSI
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buf = bytearray(4) # create buffer of size 8
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spi.write_readinto(b'abcd', buf) # write to MOSI and read from MISO into the buffer
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spi.write_readinto(buf, buf) # write buf to MOSI and read back into the buf
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Disk Access
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-----------
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Use the :ref:`zephyr.DiskAccess <zephyr.DiskAccess>` class to support filesystem::
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import vfs
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from zephyr import DiskAccess
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block_dev = DiskAccess('SDHC') # create a block device object for an SD card
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vfs.VfsFat.mkfs(block_dev) # create FAT filesystem object using the disk storage block
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vfs.mount(block_dev, '/sd') # mount the filesystem at the SD card subdirectory
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# with the filesystem mounted, files can be manipulated as normal
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with open('/sd/hello.txt','w') as f: # open a new file in the directory
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f.write('Hello world') # write to the file
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print(open('/sd/hello.txt').read()) # print contents of the file
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Flash Area
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----------
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Use the :ref:`zephyr.FlashArea <zephyr.FlashArea>` class to support filesystem::
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import vfs
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from zephyr import FlashArea
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block_dev = FlashArea(4, 4096) # creates a block device object in the frdm-k64f flash scratch partition
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vfs.VfsLfs2.mkfs(block_dev) # create filesystem in lfs2 format using the flash block device
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vfs.mount(block_dev, '/flash') # mount the filesystem at the flash subdirectory
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# with the filesystem mounted, files can be manipulated as normal
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with open('/flash/hello.txt','w') as f: # open a new file in the directory
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f.write('Hello world') # write to the file
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print(open('/flash/hello.txt').read()) # print contents of the file
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Sensor
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------
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Use the :ref:`zsensor.Sensor <zsensor.Sensor>` class to access sensor data::
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import zsensor
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from zsensor import Sensor
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accel = Sensor("FXOX8700") # create sensor object for the accelerometer
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accel.measure() # obtain a measurement reading from the accelerometer
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# each of these prints the value taken by measure()
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accel.get_float(zsensor.ACCEL_X) # print measurement value for accelerometer X-axis sensor channel as float
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accel.get_millis(zsensor.ACCEL_Y) # print measurement value for accelerometer Y-axis sensor channel in millionths
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accel.get_micro(zsensor.ACCEL_Z) # print measurement value for accelerometer Z-axis sensor channel in thousandths
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accel.get_int(zsensor.ACCEL_X) # print measurement integer value only for accelerometer X-axis sensor channel
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