使用Raspberry Pi Pico的微Python教程
最编程
2024-08-09 13:45:09
...
树莓派Pico的mpy例子，写几个作为参考使用：
import machine
import utime
sensor_temp = machine.ADC(4)
conversion_factor = 3.3 / (65535)
while True:
reading = sensor_temp.read_u16() * conversion_factor
temperature = 27 - (reading - 0.706)/0.001721
print(temperature)
utime.sleep(2)打印内置的温度传感器的温度
先初始化读取内部的ADC的值，然后用65535除一下看分度值
下面死循环，读取。
from machine import Pin, Timer
led = Pin(25, Pin.OUT)
tim = Timer()
def tick(timer):
global led
led.toggle()
tim.init(freq=2.5, mode=Timer.PERIODIC, callback=tick)from machine import Pin
p2 = Pin(2, Pin.IN, Pin.PULL_UP)
p2.irq(lambda pin: print("IRQ with flags:", pin.irq().flags()),
Pin.IRQ_FALLING)
使用内部中断，为了方便。
还是点灯
import time
import _thread
import machine
def task(n, delay):
led = machine.Pin(25, machine.Pin.OUT)
for i in range(n):
led.high()
time.sleep(delay)
led.low()
time.sleep(delay)
print('done')
_thread.start_new_thread(task, (10, 0.5))这东西是双核的嘛，所以可以使用线程来加速
我们引入微库，然后定义一个任务，后面线程要执行
代码的实现很简单，就是闪烁个LED
下面直接加到线程里面就可以执行了
就是这个
from machine import SPI
spi = SPI(0)
spi = SPI(0, 100_000)
spi = SPI(0, 100_000, polarity=1, phase=1)
spi.write('test')
spi.read(5)
buf = bytearray(3)
spi.write_readinto('out', buf)SPI在mpy里面分外简单，直接initial。然后读写操作就好了
import time
from machine import Pin, PWM
pwm = PWM(Pin(25))
pwm.freq(1000)
duty = 0
direction = 1
for _ in range(8 * 256):
duty += direction
if duty > 255:
duty = 255
direction = -1
elif duty < 0:
duty = 0
direction = 1
pwm.duty_u16(duty * duty)
time.sleep(0.001)使用PWM模块实现LED的亮暗变化
先指定引脚，然后是频率，for的时候用了一个占位符
下面的逻辑是实现了，从小到大和从小到大
控制一个WS2812
# 控制WS2812
import array
import time
from machine import Pin
import rp2
# 分配一个管脚
NUM_LEDS = 8
@rp2.asm_pio(sideset_init=rp2.PIO.OUT_LOW, out_shiftdir=rp2.PIO.SHIFT_LEFT, autopull=True, pull_thresh=24)
def ws2812():
T1 = 2
T2 = 5
T3 = 3
wrap_target()
label("bitloop")
out(x, 1) .side(0)[T3 - 1]
jmp(not_x, "do_zero") .side(1)[T1 - 1]
jmp("bitloop") .side(1)[T2 - 1]
label("do_zero")
nop() .side(0)[T2 - 1]
wrap()
sm = rp2.StateMachine(0, ws2812, freq=8_000_000, sideset_base=Pin(22))
sm.active(1)
ar = array.array("I", [0 for _ in range(NUM_LEDS)])
for i in range(4 * NUM_LEDS):
for j in range(NUM_LEDS):
r = j * 100 // (NUM_LEDS - 1)
b = 100 - j * 100 // (NUM_LEDS - 1)
if j != i % NUM_LEDS:
r >>= 3
b >>= 3
ar[j] = r << 16 | b
sm.put(ar, 8)
time.sleep_ms(50)
for i in range(24):
for j in range(NUM_LEDS):
ar[j] >>= 1
sm.put(ar, 8)
time.sleep_ms(50)
用了一点神奇的东西，这个pico有状态引脚
@rp2.asm_pio(sideset_init=rp2.PIO.OUT_LOW, out_shiftdir=rp2.PIO.SHIFT_LEFT, autopull=True, pull_thresh=24)
def ws2812():
T1 = 2
T2 = 5
T3 = 3
wrap_target()
label("bitloop")
out(x, 1) .side(0)[T3 - 1]
jmp(not_x, "do_zero") .side(1)[T1 - 1]
jmp("bitloop") .side(1)[T2 - 1]
label("do_zero")
nop() .side(0)[T2 - 1]
wrap()就是这段，描述了我们ws2812的控制协议
from machine import Pin, I2C
i2c = I2C(0, scl=Pin(9), sda=Pin(8), freq=100000)
i2c.scan()
i2c.writeto(76, b'123')
i2c.readfrom(76, 4)
i2c = I2C(1, scl=Pin(7), sda=Pin(6), freq=100000)
i2c.scan()
i2c.writeto_mem(76, 6, b'456')
i2c.readfrom_mem(76, 6, 4)I2C普通的demo，设置引脚，freq
然后扫描一下地址，剩下的命令就是读写了，很常见
普通的I2C的屏幕
from machine import Pin, I2C
from ssd1306 import SSD1306_I2C
import framebuf
WIDTH = 128
HEIGHT = 32
i2c = I2C(0)
print("I2C Address : "+hex(i2c.scan()[0]).upper())
print("I2C Configuration: "+str(i2c))
oled = SSD1306_I2C(WIDTH, HEIGHT, i2c)
buffer = bytearray(b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00|?\x00\x01\x86@\x80\x01\x01\x80\x80\x01\x11\x88\x80\x01\x05\xa0\x80\x00\x83\xc1\x00\x00C\xe3\x00\x00~\xfc\x00\x00L'\x00\x00\x9c\x11\x00\x00\xbf\xfd\x00\x00\xe1\x87\x00\x01\xc1\x83\x80\x02A\x82@\x02A\x82@\x02\xc1\xc2@\x02\xf6>\xc0\x01\xfc=\x80\x01\x18\x18\x80\x01\x88\x10\x80\x00\x8c!\x00\x00\x87\xf1\x00\x00\x7f\xf6\x00\x008\x1c\x00\x00\x0c \x00\x00\x03\xc0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00")
fb = framebuf.FrameBuffer(buffer, 32, 32, framebuf.MONO_HLSB)
oled.fill(0)
oled.blit(fb, 96, 0)
oled.text("Raspberry Pi", 5, 5)
oled.text("Pico", 5, 15)
oled.show()
驱动普通的SSD1306屏幕，驱动是提前移植好的
https://www.raspberrypi.org/documentation/rp2040/getting-started/#rp2040-boards参考资料在这里
C/C++ SDK
Python SDK
还有很多有趣的代码没有写，参考来自官网资料~
https://datasheets.raspberrypi.org/pico/raspberry-pi-pico-c-sdk.pdfhttps://datasheets.raspberrypi.org/pico/raspberry-pi-pico-python-sdk.pdfhttps://docs.micropython.org/en/latest/library/_thread.html上一篇： Swift 04：流程控制指南