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mcp3008.py
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/
mcp3008.py
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#!/usr/bin/env python
##^-----------------^ required to make executable
#use 'sudo chmod +x filename.py' to make exec
#use 'sudo ./filename.py' to run in terminal
import RPi.GPIO as GPIO
import os
import eeml
GPIO.setmode(GPIO.BCM)
#read SPI data from MPC3008 chip, 8 possible ADC inputs (0-7)
def readadc(adcnum, clockpin, mosipin, misopin, cspin):
#reject invalid adc pin numbers
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, whatis '|=' operator
commandout <<=3 #only need to send 5 bits here, whatis '<<=' operator
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 one empty bit, one null bit, 10 ADC bits
for i in range(12):
GPIO.output(clockpin, True)
GPIO.output(clockpin, False)
adcout <<=1
if (GPIO.input(misopin)):
adcout |= 0x1
GPIO.output(cspin, True)
adcout /= 2 #first bit is 'null', drop it
return adcout