SPI

MCP4911 and MCP3008

#!/usr/bin/env python
import spidev
import time

def write(value, cs):
    """"
    #Set chipSelect HIGH
    GPIO.output(cs, True)
    #Set clock LOW
    GPIO.output(clock, False)
    #Set chipSelect LOW
    GPIO.output(cs, False)
    
    for i in range(12):
        if (commandout & 0x08000):
            GPIO.output(mosi, True)
        else:
            GPIO.output(mosi, False)
        commandout <<= 1
        GPIO.output(clockpin, True)
        GPIO.output(clockpin, True)
    """    
    commandout = 0b10011
    commandout <<= 10
    commandout ^= value
    commandout <<= 2
    
    #Create spi object
    spi = spidev.SpiDev()
    #open port
    spi.open(0,cs)
    #send command
    spi.xfer2([commandout])
    for i in range(12):
        spi.xfer2([(commandout & 0x08000)])
        commandout <<= 1
    
def read(adcnum, cs):
    if((adcnum > 7) or (adcnum < 0)):
        return -1
    #create spi
    spi = spidev.SpiDev()
    #open port
    spi.open(0,cs)
    #send command transfer receive result
    r = spi.xfer2([1,(8+adcnum)<<4,0])
    #close connection
    spi.close()
    #parse result
    adcout = ((r[1]&3) << 8) + r[2]
    return adcout

try:
    #Main logic
    while True:
        for i in range(254):
            write(i,0)
            time.sleep(0.1)
        for i in range(254):
            write(254-i,0)
            time.sleep(0.1)
except KeyboardInterrupt: