raspberry-gpio-python雜記

★GPIO.RISING  正緣觸發參數   GPIO.FALLING 負緣觸發參數

★中斷  軟體中斷才會耗用CPU資源，又叫做系統呼叫。
到底是raspberry Pi 板子本身就有硬體中斷，還是GPIO做出軟體中斷?

★有關input 上/下拉電阻，event_detect，debouce...

★參考https://sourceforge.net/p/raspberry-gpio-python/wiki/BasicUsage/

GPIO.setmode(GPIO.BOARD)
  # or
GPIO.setmode(GPIO.BCM)

mode = GPIO.getmode()
GPIO.setwarnings(False)
GPIO.setup(channel, GPIO.IN)
GPIO.setup(channel, GPIO.OUT)
GPIO.setup(channel, GPIO.OUT, initial=GPIO.HIGH)
----------------------------
chan_list = [11,12]    # add as many channels as you want!
                       # you can tuples instead i.e.:
                       #   chan_list = (11,12)
GPIO.setup(chan_list, GPIO.OUT)
-----------------------------
取得值GPIO.input(channel)
設定值GPIO.output(channel, state)
多組設定
chan_list = [11,12]                             # also works with tuples
GPIO.output(chan_list, GPIO.LOW)                # sets all to GPIO.LOW
GPIO.output(chan_list, (GPIO.HIGH, GPIO.LOW))   # sets first HIGH and second LOW

清除所有腳位，恢復初始狀態GPIO.cleanup()
也可以只清部份
GPIO.cleanup(channel)
GPIO.cleanup( (channel1, channel2) )
GPIO.cleanup( [channel1, channel2] )
取得軟硬體資訊


GPIO.RPI_INFO
GPIO.RPI_INFO['P1_REVISION']
GPIO.RPI_REVISION
GPIO.VERSION

★def mycallback(channel):
     print("Button pressed")
在上面中參數channel沒有作用，但不可以除去，否則會有runtime error，一定至少要有一個參數，在這裡至於給什麼，都可以。

★有提示的輸入
pitch_s = raw_input("Enter Pitch 200 to 2000): ")
 duration_s = raw_input("Enter Duration second): ")

★def buzz(pitch, duration) :    頻率  時間
 period = 1.0 / pitch            period 是週期，振動一次花的時間
 half_period = period / 2
 cycles = int(duration * pitch)  頻率 X 時間  = 總共振動的次數
 for i in xrange(cycles) :
     GPIO.output(buzzer_pin, GPIO.HIGH)
     time.sleep(half_period)

     GPIO.output(buzzer_pin, GPIO.LOW)

     time.sleep(half_period)