Turtorial Examples for RpiZero-MicroPython

2020/3/10

Turtorial Examples for RpiZero-MicroPython

RpiZero_BareMetal

Quick reference for the Raspberry Pi Zero W MicroPython

LED Blink

LEDonBoard_blink.py

  import utime
  from machine import Pin
  # set gpio47 to output mode
  led=Pin(47,Pin.OUT) # LED on board
  while(1):
      led(0)  # LED on
      utime.sleep_ms(300)
      led(1)  # LED off
      utime.sleep_ms(300)
  

Pin/GPIO

  from machine import Pin

  ld = Pin(47, Pin.OUT)   # create output pin on GPIO47 (on-board LED)
  ld.value(0)             # set pin to off/low
  ld(1)                   # set pin to on/high

  p0 = Pin(17, Pin.IN)    # create input pin on GPIO17 (board pin #11)
  print(p0.value())       # get value, 0 or 1

  p2 = Pin(27, Pin.IN, Pin.PULL_UP) # enable internal pull-up resistor
  p2.value()
  p3 = Pin(22, Pin.OUT, value=1) # set pin high on creation
  p3.value()
  p3 = Pin(22, Pin.OUT, value=0)
  p3.value()
  

PWM

The hardware PWM only works on following pins:
GPIO12, GPIO18, GPIO40, GPIO52 for PWM0,
GPIO13, GPIO19, GPIO41, GPIO45, GPIO53 for PWM1.

You may also use ID of 0 or 1 without specifying output pin
if you want to configure alternate functions separately.

The default PWM system clock is configured to be 960KHz and
the default PWM period is 960.
It means that the default PWM output frequency is 1KHz
and you can change its duty cycle in 1/960 step.

  import math
  from time import sleep
  from machine import PWM, Pin

  p18 = PWM(Pin(18))   # use GPIO18(p12) for PWM0
  p18.init(freq=1000)  # 1000Hz (ticks = 960000/freq)

  for p in range(100):
    p18.duty_u16(math.floor(65536*p/100))# PWM duty = arg/65536
    sleep(0.05)
  for p in range(100):
    p18.duty_u16(math.floor(65536-65536*p/100))
    sleep(0.05)

  p18.active(False)    # stop PWM0 output

  

ADC

Hardware is not available.

SPI

The hardware SPI bus only works on following pins:
MOSI is board pin #19 = GPIO10,
MISO is board pin #21 = GPIO9,
SCK is board pin #23 = GPIO11.
Software SPI is currently not implemented.

Use the machine.SPI class with bus ID of 0. .

see NeoPixel(are using SPI)

I2C

The hardware I2C bus only works on following pins:
SDA is board pin #3 = GPIO2,
SCL is board pin #5 = GPIO3.
Software I2C is currently not implemented.

Use the machine.I2C class with bus ID of 1.
Bus 0 and bus 2 are not available for users.

Nucleo_TMP102_test.py

  # Nucleo
  import utime
  from machine import Pin, I2C
  from tmp102 import Tmp102
  i2c = I2C(1)
  sensor = Tmp102(i2c, 0x48)

  while True:
     print('Temperature: {0:.1f}'.format(sensor.temperature))
     utime.sleep(2)

  

RpiZero_demo_i2c_LCD.py

  # Note: VCC needs 5V
  import i2c_lcd
  from machine import Pin,I2C
  from time import sleep

  i2c = I2C(1)

  d = i2c_lcd.Display(i2c)

  d.clear()

  d.home()
  d.write('LCD I2C test .py')
  d.move(0,1)
  d.write('Hello World        ')
  d.color(0xFF,0,0)
  sleep(0.5)
  d.color(0,0xFF,0)
  sleep(0.5)
  d.color(0,0,0xFF)
  sleep(0.5)
  d.color(0x44,0xFF,0x44)
  

RTC

Not Implemeted??

>>> from machine import RTC
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
  ImportError: cannot import name RTC
  >>> 
  

NeoPixel

module install:

  git clone https://github.com/JanBednarik/micropython-ws2812.git
  cd micropython-ws2812

  Patch ws2812.py to ws2812_rpi.py as follows:

  patch#1:
  import pyb
  ->
  import machine as pyb

  patch#2:
  self.spi = pyb.SPI(spi_bus, pyb.SPI.MASTER, baudrate=3200000, polarity=0, phase=1)
  ->
  self.spi = pyb.SPI(spi_bus,baudrate=3200000, polarity=0, phase=1)

  patch#3:
  self.spi.send(self.buf)
  ->
  self.spi.write(self.buf)

  patch#4
          gc.collect()
  ->
  #        gc.collect()
  # don't use gc.collect(), that take a time because of having huge RAM

  Copy ws2812_rpi.py to boot SD.

  

sample1:

  # connect the following pin to DIN of nexpixels
  # Pin#19 = GPIO10 (if spi_bus=0)
  from ws2812_rpi import WS2812
  chain = WS2812(spi_bus=0, led_count=4)
  data = [
      (255, 0, 0),    # red
      (0, 255, 0),    # greenp
      (0, 0, 255),    # blue
      (85, 85, 85),   # white
  ]
  chain.show(data)

  

sample2:

  from time import sleep
  import math
  from ws2812_rpi import WS2812

  ring = WS2812(spi_bus=0, led_count=16, intensity=0.1)

  def data_generator(led_count):
      data = [(0, 0, 0) for i in range(led_count)]
      step = 0
      while True:
          red = int((1 + math.sin(step * 0.1324)) * 127)
          green = int((1 + math.sin(step * 0.1654)) * 127)
          blue = int((1 + math.sin(step * 0.1)) * 127)
          data[step % led_count] = (red, green, blue)
          yield data
          step += 1

  for data in data_generator(ring.led_count):
      ring.show(data)
      sleep(0.01)

  

DHT

N.A.

Networking

N.A.

Performance Test

performanceRpiZero.py

  # Peformace Test RpiZero
  import time
  def performanceTest():
      msec = time.ticks_ms
      endTime = msec() + 10000
      count = 0
      while msec() < endTime:
          count += 1
      print("Count: ", count)

  performanceTest()

  

以上