circuitpython/docs/quickref.rst

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.. _quickref:
Quick reference for the pyboard
===============================
.. image:: http://micropython.org/resources/pybv10-pinout.jpg
:alt: PYBv1.0 pinout
2014-10-26 18:58:18 -04:00
:width: 700px
General board control
---------------------
See :mod:`pyb`. ::
import pyb
pyb.delay(50) # wait 50 milliseconds
pyb.millis() # number of milliseconds since bootup
pyb.repl_uart(pyb.UART(1, 9600)) # duplicate REPL on UART(1)
pyb.wfi() # pause CPU, waiting for interrupt
pyb.freq() # get CPU and bus frequencies
pyb.freq(60000000) # set CPU freq to 60MHz
pyb.stop() # stop CPU, waiting for external interrupt
LEDs
----
See :ref:`pyb.LED <pyb.LED>`. ::
from pyb import LED
led = LED(1) # red led
led.toggle()
led.on()
led.off()
Pins and GPIO
-------------
See :ref:`pyb.Pin <pyb.Pin>`. ::
from pyb import Pin
p_out = Pin('X1', Pin.OUT_PP)
p_out.high()
p_out.low()
p_in = Pin('X2', Pin.IN, Pin.PULL_UP)
p_in.value() # get value, 0 or 1
External interrupts
-------------------
See :ref:`pyb.ExtInt <pyb.ExtInt>`. ::
from pyb import Pin, ExtInt
callback = lambda e: print("intr")
ext = ExtInt(Pin('Y1'), ExtInt.IRQ_RISING, Pin.PULL_NONE, callback)
Timers
------
See :ref:`pyb.Timer <pyb.Timer>`. ::
from pyb import Timer
tim = Timer(1, freq=1000)
tim.counter() # get counter value
tim.freq(0.5) # 0.5 Hz
tim.callback(lambda t: pyb.LED(1).toggle())
PWM (pulse width modulation)
----------------------------
See :ref:`pyb.Pin <pyb.Pin>` and :ref:`pyb.Timer <pyb.Timer>`. ::
from pyb import Pin, Timer
p = Pin('X1') # X1 has TIM2, CH1
tim = Timer(2, freq=1000)
ch = tim.channel(1, Timer.PWM, pin=p)
ch.pulse_width_percent(50)
ADC (analog to digital conversion)
----------------------------------
See :ref:`pyb.Pin <pyb.Pin>` and :ref:`pyb.ADC <pyb.ADC>`. ::
from pyb import Pin, ADC
adc = ADC(Pin('X19'))
adc.read() # read value, 0-4095
DAC (digital to analog conversion)
----------------------------------
See :ref:`pyb.Pin <pyb.Pin>` and :ref:`pyb.DAC <pyb.DAC>`. ::
from pyb import Pin, DAC
dac = DAC(Pin('X5'))
dac.write(120) # output between 0 and 255
UART (serial bus)
-----------------
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
SPI bus
-------
See :ref:`pyb.SPI <pyb.SPI>`. ::
from pyb import SPI
spi = SPI(1, SPI.MASTER, baudrate=200000, polarity=1, phase=0)
spi.send('hello')
spi.recv(5) # receive 5 bytes on the bus
spi.send_recv('hello') # send a receive 5 bytes
I2C bus
-------
See :ref:`pyb.I2C <pyb.I2C>`. ::
from pyb import I2C
i2c = I2C(1, I2C.MASTER, baudrate=100000)
i2c.scan() # returns list of slave addresses
i2c.send('hello', 0x42) # send 5 bytes to slave with address 0x42
i2c.recv(5, 0x42) # receive 5 bytes from slave
i2c.mem_read(2, 0x42, 0x10) # read 2 bytes from slave 0x42, slave memory 0x10
i2c.mem_write('xy', 0x42, 0x10) # write 2 bytes to slave 0x42, slave memory 0x10