.. _quickref:

墨星stm32快速参考
===============================

.. image:: tutorial/img/moxing-STM32-pinout.jpg
    :alt: moxing stm32 pinout
    :width: 700px

通用硬件控制
---------------------

See :mod:`pyb`. ::

    import pyb

    pyb.repl_uart(pyb.UART(2, 9600)) # duplicate REPL on UART(2)在UART（2）上重置REPL
    pyb.wfi() # pause CPU, waiting for interrupt 暂停cpu，等待中断
    pyb.freq() # get CPU and bus frequencies 获得CPU频率
    pyb.freq(60000000) # set CPU freq to 60MHz 设置CPU频率
    pyb.stop() # stop CPU, waiting for external interrupt 停止cpu，等待外部中断

延时和时间
----------------

Use the :mod:`time <utime>` module::

    import time

    time.sleep(1)           # sleep for 1 second 延时1s
    time.sleep_ms(500)      # sleep for 500 milliseconds 延时500ms
    time.sleep_us(10)       # sleep for 10 microseconds 延时10us
    start = time.ticks_ms() # get value of millisecond counter 获取毫秒计数器的值
    delta = time.ticks_diff(time.ticks_ms(), start) # compute time difference 计算时间差

Pins and GPIO
-------------

See :ref:`pyb.Pin <pyb.Pin>`. ::

    from pyb import Pin

    p_out = Pin('P1', Pin.OUT_PP)
    p_out.high()
    p_out.low()

    p_in = Pin('P2', Pin.IN, Pin.PULL_UP)
    p_in.value() # get value, 0 or 1

外部中断
-------------------

See :ref:`pyb.ExtInt <pyb.ExtInt>`. ::

    from pyb import Pin, ExtInt

    callback = lambda e: print("intr")
    ext = ExtInt(Pin('P1'), ExtInt.IRQ_RISING, Pin.PULL_UP, callback)

定时器
------

See :ref:`pyb.Timer <pyb.Timer>`. ::

    from pyb import Timer

    tim = Timer(1, freq=1000)
    tim.counter() # get counter value 获取计时器值
    tim.freq(0.5) # 0.5 Hz
    tim.callback(lambda t: print('count'))

PWM脉宽调制
----------------------------

See :ref:`pyb.Pin <pyb.Pin>` and :ref:`pyb.Timer <pyb.Timer>`. ::

    from pyb import Pin, Timer

    p = Pin('P1') # P1 has TIM1, CH2N
    tim = Timer(1, freq=1000)
    ch = tim.channel(2, Timer.PWM, pin=p)
    ch.pulse_width_percent(50)

ADC (模数转换)
----------------------------------

See :ref:`pyb.Pin <pyb.Pin>` and :ref:`pyb.ADC <pyb.ADC>`. ::

    from pyb import Pin, ADC

    adc = ADC(Pin('A1'))
    adc.read() # read value,读取值 0-4095

DAC (数模转换)
----------------------------------

See :ref:`pyb.Pin <pyb.Pin>` and :ref:`pyb.DAC <pyb.DAC>`. ::

    from pyb import Pin, DAC

    dac = DAC(Pin('A2'))
    dac.write(120) # 输出介于0-255

UART (串行总线)
-----------------

See :ref:`pyb.UART <pyb.UART>`. ::

    from pyb import UART

    uart = UART(1, 9600)
    uart.write('hello')
    uart.read(5) # read up to 5 bytes 读取5个字节

SPI总线
-------

See :ref:`pyb.SPI <pyb.SPI>`. ::

    from pyb import SPI

    spi = SPI(2, SPI.MASTER, baudrate=200000, polarity=1, phase=0)
    spi.send('hello')
    spi.recv(5) # receive 5 bytes on the bus 在总线上接收5个字节
    spi.send_recv('hello') # send and receive 5 bytes 发送5个字节

I2C bus
-------

See :ref:`pyb.I2C <pyb.I2C>`. ::

    from pyb import I2C

    i2c = I2C(2, I2C.MASTER, baudrate=100000)
    i2c.scan() # returns list of slave addresses 返回一个从属设备地址的列表
    i2c.send('hello', 0x42) # send 5 bytes to slave with address 0x42 使用0x42地址向从属设备发送5个字节
    i2c.recv(5, 0x42) # receive 5 bytes from slave 从从属设备上接收5个字节
    i2c.mem_read(2, 0x42, 0x10) # read 2 bytes from slave 0x42, slave memory 0x10 从地址为0x42从属设备上接收2个字节，从属存储器为0x10
    i2c.mem_write('xy', 0x42, 0x10) # write 2 bytes to slave 0x42, slave memory 0x10 向地址为0x42的从属设备写入2个字节，从属存储器为0x10