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diff --git a/docs/zephyr/quickref.rst b/docs/zephyr/quickref.rst new file mode 100644 index 000000000..783621316 --- /dev/null +++ b/docs/zephyr/quickref.rst @@ -0,0 +1,157 @@ +.. _zephyr_quickref: + +Quick reference for the Zephyr port +=================================== + +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: + +.. toctree:: + :maxdepth: 1 + + general.rst + tutorial/index.rst + +Running MicroPython +------------------- + +See the corresponding section of the tutorial: :ref:`intro`. + +Delay and timing +---------------- + +Use the :mod:`time <utime>` module:: + + import time + + time.sleep(1) # sleep for 1 second + time.sleep_ms(500) # sleep for 500 milliseconds + time.sleep_us(10) # sleep for 10 microseconds + start = time.ticks_ms() # get millisecond counter + delta = time.ticks_diff(time.ticks_ms(), start) # compute time difference + +Pins and GPIO +------------- + +Use the :ref:`machine.Pin <machine.Pin>` class:: + + from machine import Pin + + pin = Pin(("GPIO_1", 21), Pin.IN) # create input pin on GPIO1 + print(pin) # print pin port and number + + pin.init(Pin.OUT, Pin.PULL_UP, value=1) # reinitialize pin + + pin.value(1) # set pin to high + pin.value(0) # set pin to low + + pin.on() # set pin to high + pin.off() # set pin to low + + pin = Pin(("GPIO_1", 21), Pin.IN) # create input pin on GPIO1 + + pin = Pin(("GPIO_1", 21), Pin.OUT, value=1) # set pin high on creation + + pin = Pin(("GPIO_1", 21), Pin.IN, Pin.PULL_UP) # enable internal pull-up resistor + + switch = Pin(("GPIO_2", 6), Pin.IN) # create input pin for a switch + switch.irq(lambda t: print("SW2 changed")) # enable an interrupt when switch state is changed + +Hardware I2C bus +---------------- + +Hardware I2C is accessed via the :ref:`machine.I2C <machine.I2C>` class:: + + from machine import I2C + + i2c = I2C("I2C_0") # construct an i2c bus + print(i2c) # print device name + + i2c.scan() # scan the device for available I2C slaves + + i2c.readfrom(0x1D, 4) # read 4 bytes from slave 0x1D + i2c.readfrom_mem(0x1D, 0x0D, 1) # read 1 byte from slave 0x1D at slave memory 0x0D + + i2c.writeto(0x1D, b'abcd') # write to slave with address 0x1D + i2c.writeto_mem(0x1D, 0x0D, b'ab') # write to slave 0x1D at slave memory 0x0D + + buf = bytearray(8) # create buffer of size 8 + i2c.writeto(0x1D, b'abcd') # write buf to slave 0x1D + +Hardware SPI bus +---------------- + +Hardware SPI is accessed via the :ref:`machine.SPI <machine.SPI>` class:: + + from machine import SPI + + spi = SPI("SPI_0") # construct a spi bus with default configuration + spi.init(baudrate=100000, polarity=0, phase=0, bits=8, firstbit=SPI.MSB) # set configuration + + # equivalently, construct spi bus and set configuration at the same time + spi = SPI("SPI_0", baudrate=100000, polarity=0, phase=0, bits=8, firstbit=SPI.MSB) + print(spi) # print device name and bus configuration + + spi.read(4) # read 4 bytes on MISO + spi.read(4, write=0xF) # read 4 bytes while writing 0xF on MOSI + + buf = bytearray(8) # create a buffer of size 8 + spi.readinto(buf) # read into the buffer (reads number of bytes equal to the buffer size) + spi.readinto(buf, 0xF) # read into the buffer while writing 0xF on MOSI + + spi.write(b'abcd') # write 4 bytes on MOSI + + buf = bytearray(4) # create buffer of size 8 + spi.write_readinto(b'abcd', buf) # write to MOSI and read from MISO into the buffer + spi.write_readinto(buf, buf) # write buf to MOSI and read back into the buf + +Disk Access +----------- + +Use the :ref:`zephyr.DiskAccess <zephyr.DiskAccess>` class to support filesystem:: + + import os + from zephyr import DiskAccess + + block_dev = DiskAccess('SDHC') # create a block device object for an SD card + os.VfsFat.mkfs(block_dev) # create FAT filesystem object using the disk storage block + os.mount(block_dev, '/sd') # mount the filesystem at the SD card subdirectory + + # with the filesystem mounted, files can be manipulated as normal + with open('/sd/hello.txt','w') as f: # open a new file in the directory + f.write('Hello world') # write to the file + print(open('/sd/hello.txt').read()) # print contents of the file + +Flash Area +---------- + +Use the :ref:`zephyr.FlashArea <zephyr.FlashArea>` class to support filesystem:: + + import os + from zephyr import FlashArea + + block_dev = FlashArea(4, 4096) # creates a block device object in the frdm-k64f flash scratch partition + os.VfsLfs2.mkfs(block_dev) # create filesystem in lfs2 format using the flash block device + os.mount(block_dev, '/flash') # mount the filesystem at the flash subdirectory + + # with the filesystem mounted, files can be manipulated as normal + with open('/flash/hello.txt','w') as f: # open a new file in the directory + f.write('Hello world') # write to the file + print(open('/flash/hello.txt').read()) # print contents of the file + +Sensor +------ + +Use the :ref:`zsensor.Sensor <zsensor.Sensor>` class to access sensor data:: + + import zsensor + from zsensor import Sensor + + accel = Sensor("FXOX8700") # create sensor object for the accelerometer + + accel.measure() # obtain a measurement reading from the accelerometer + + # each of these prints the value taken by measure() + accel.float(zsensor.ACCEL_X) # print measurement value for accelerometer X-axis sensor channel as float + accel.millis(zsensor.ACCEL_Y) # print measurement value for accelerometer Y-axis sensor channel in millionths + accel.micro(zsensor.ACCEL_Z) # print measurement value for accelerometer Z-axis sensor channel in thousandths + accel.int(zsensor.ACCEL_X) # print measurement integer value only for accelerometer X-axis sensor channel |