PythonLED制御サンプルプログラム

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＊サンプルプログラムです。RasPi5の環境の差で動かないこともありますので自己責任で
　行ってください。
　教則本を基にして爺さんが編集したもので爺さんのRasPi5で動作したプログラムです
　（SPI設定が　desable　で動作しました）
　デバッグのために　無駄な　print文が入っています

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import time
import os
import RPi.GPIO as GPIO

# change these as desired - they're the pins connected from the
# SPI port on the ADC to the Cobbler
SPICLK = 11
SPIMISO = 9
SPIMOSI = 10
SPICS = 8
#set BCM_GPIO 18(GPIO1) as LED pin
#sudo raspi-config : Interface -> SPI off
#
#LEDPIN = 17
LEDPIN = 18

analogChannel = 0

#setup function for some setup---custom function
def setup():
   global p
   GPIO.setwarnings(False)
   #set the gpio modes to BCM numbering
   GPIO.setmode(GPIO.BCM)
   # set up the SPI interface pins
   GPIO.setup(SPIMOSI, GPIO.OUT)
   GPIO.setup(SPIMISO, GPIO.IN)
   GPIO.setup(SPICLK, GPIO.OUT)
   GPIO.setup(SPICS, GPIO.OUT)
   #set all LedPin's mode to output,and initial level to HIGH(3.3V)
   GPIO.setup(LEDPIN,GPIO.OUT,initial=GPIO.LOW)
   #set LEDPIN as PWM output,and frequency=100Hz
   p = GPIO.PWM(LEDPIN,100)
   #set p begin with ualue 0
   p.start(0)
   pass


# read SPI data from MCP3008 chip, 8 possible adc's (0 thru 7)
def readadc(adcnum, clockpin, mosipin, misopin, cspin):
       if ((adcnum > 7) or (adcnum < 0)):
               return -1
       GPIO.output(cspin, True)

       GPIO.output(clockpin, False)  # start clock low
       GPIO.output(cspin, False)     # bring CS low

       commandout = adcnum
       commandout |= 0x18  # start bit + single-ended bit
       commandout <<= 3    # we only need to send 5 bits here
       for i in range(5):
               if (commandout & 0x80):
                       GPIO.output(mosipin, True)
               else:
                       GPIO.output(mosipin, False)
               commandout <<= 1
               GPIO.output(clockpin, True)
               GPIO.output(clockpin, False)

       adcout = 0
       # read in one empty bit, one null bit and 10 ADC bits
       for i in range(12):
               GPIO.output(clockpin, True)
               GPIO.output(clockpin, False)
               adcout <<= 1
               if (GPIO.input(misopin)):
                        adcout |= 0x1
               
#                print ('serial input ADC = %d  shift:%d'%(adcout,i))

       GPIO.output(cspin, True)
       adcout >>= 1       # first bit is 'null' so drop it
       return adcout

#main function
def main():

   while True:
       adc = readadc(analogChannel, SPICLK, SPIMOSI, SPIMISO, SPICS)
#        print ('LightSensor ADC = %d'%(adc))
       adcdu=(1023-adc)*100/1023

       print ('LightSensor ADC = %d (duty:%d)'%(adc,adcdu))

       p.ChangeDutyCycle(int(adcdu))
       time.sleep(0.5)

#define a destroy function for clean up everything after the script finished
def destroy():
   #stop p
   p.stop()
   #turn off led
   GPIO.output(LEDPIN,GPIO.LOW)
   #release resource
   GPIO.cleanup()
   
#
# if run this script directly ,do:
if __name__ == '__main__':
   setup()
   try:
           main()
   #when 'Ctrl+C' is pressed,child program destroy() will be executed.
   except KeyboardInterrupt:
       destroy()

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