MCP3208 troubleshooting notes

I tried to do ADC for all channels but always found even channels almost always work, and odd number channels always fail.


*** Start Program - FongToy v1.26 tlfong01 2013may28 ***

Analog voltage at channel number  0x0  =  2.498
Analog voltage at channel number  0x1  =  59.749
Analog voltage at channel number  0x2  =  3.336
Analog voltage at channel number  0x3  =  0.0
Analog voltage at channel number  0x4  =  3.33
Analog voltage at channel number  0x5  =  58.789
Analog voltage at channel number  0x6  =  2.498
Analog voltage at channel number  0x7  =  57.344

*** Stop Program ***

pi@raspberrypi ~/fongtoy $ sudo python fongtoy.py

*** Start Program - FongToy v1.26 tlfong01 2013may28 ***

Analog voltage at channel number  0x0  =  2.498
Analog voltage at channel number  0x1  =  59.761
Analog voltage at channel number  0x2  =  3.326
Analog voltage at channel number  0x3  =  57.344
Analog voltage at channel number  0x4  =  3.336
Analog voltage at channel number  0x5  =  1.446
Analog voltage at channel number  0x6  =  59.842
Analog voltage at channel number  0x7  =  57.344

*** Stop Program ***

pi@raspberrypi ~/fongtoy $ sudo python fongtoy.py

*** Start Program - FongToy v1.26 tlfong01 2013may28 ***

Analog voltage at channel number  0x0  =  2.498
Analog voltage at channel number  0x1  =  59.768
Analog voltage at channel number  0x2  =  3.327
Analog voltage at channel number  0x3  =  57.344
Analog voltage at channel number  0x4  =  3.332
Analog voltage at channel number  0x5  =  1.446
Analog voltage at channel number  0x6  =  59.843
Analog voltage at channel number  0x7  =  57.344

*** Stop Program ***

pi@raspberrypi ~/fongtoy $ sudo python fongtoy.py

*** Start Program - FongToy v1.26 tlfong01 2013may28 ***

Analog voltage at channel number  0x0  =  2.498
Analog voltage at channel number  0x1  =  59.741
Analog voltage at channel number  0x2  =  3.34
Analog voltage at channel number  0x3  =  0.0
Analog voltage at channel number  0x4  =  3.334
Analog voltage at channel number  0x5  =  58.793
Analog voltage at channel number  0x6  =  2.497
Analog voltage at channel number  0x7  =  0.0

*** Stop Program ***


# ftadc.py v1.4 tlfong01 2013may27

import spidev
import time

import ftprint
import ftspi

# *****************************************************************************
# Function - TestAdcMcp3208 
# ***************************************************************************** 

def TestMcp3208v03(): # v0.3 tlfong01 2013may28

    # ftprint.PrintDoubleSpaceLine("*** Start testing MCP3208 ADC ***")   

    spiChannel = spidev.SpiDev() 
    spiChannel.open(0, 1)  

    time.sleep(0.1)

    CommonMode = 0
    DifferentialMode = 1
    SingleEndModeFirstByte = 0x06
    DifferentialModeFirstByte = 0x04

    controlTripleByte = [0x00, 0x00, 0x00]
    resultTripleByte = [0x00, 0x00, 0x00]

    for channelNumber in range(8):
        controlTripleByte[0] = SingleEndModeFirstByte | (channelNumber >> 2)
        controlTripleByte[1] = channelNumber << 6
        controlTripleByte[2] = 0x00 # don't care, actually
        resultTripleByte = spiChannel.xfer2(controlTripleByte) 
        resultDecimal =  (resultTripleByte[1] * (2 ** 8)) + (resultTripleByte[2])
        resultVoltage = (float(resultDecimal) / 4096) * 4.096     
        print "Analog voltage at channel number ", hex(channelNumber), " = ", resultVoltage

    spiChannel.close() 

    time.sleep(0.1)

    # ftprint.PrintDoubleSpaceLine("*** Stop testing MCP3208 ***")


def TestMcp3208v02(inputMode, channelNumber): # v0.2 tlfong01 2013may28

    # ftprint.PrintDoubleSpaceLine("*** Start testing MCP3208 ADC ***")   

    spiChannel = spidev.SpiDev() 
    spiChannel.open(0, 1)  

    time.sleep(0.1)

    CommonMode = 0
    DifferentialMode = 1
    SingleEndModeFirstByte = 0x06
    DifferentialModeFirstByte = 0x04

    controlTripleByte = [0x00, 0x00, 0x00]
    resultTripleByte = [0x00, 0x00, 0x00]

    controlTripleByte[0] = SingleEndModeFirstByte | (channelNumber >> 2)
    controlTripleByte[1] = channelNumber << 6
    controlTripleByte[2] = 0x00 # don't care, actually

    resultTripleByte = spiChannel.xfer2(controlTripleByte) 

    # ftprint.PrintEightBitPattern("ADC output byte 0 = ", resultTripleByte[0])
    # ftprint.PrintEightBitPattern("ADC output byte 1 = ", resultTripleByte[1])
    # ftprint.PrintEightBitPattern("ADC output byte 2 = ", resultTripleByte[2])

    resultDecimal =  (resultTripleByte[1] * (2 ** 8)) + (resultTripleByte[2])
    resultVoltage = (float(resultDecimal) / 4096) * 4.096     
    print "Analog voltage at channel number ", channelNumber, " = ", resultVoltage

    resultDecimal =  (resultTripleByte[1] * (2 ** 8)) + (resultTripleByte[2])
    resultVoltage = (float(resultDecimal) / 4096) * 4.096     
    print "Analog voltage at channel number ", channelNumber, " = ", resultVoltage
    
    resultDecimal =  (resultTripleByte[1] * (2 ** 8)) + (resultTripleByte[2])
    resultVoltage = (float(resultDecimal) / 4096) * 4.096     
    print "Analog voltage at channel number ", channelNumber, " = ", resultVoltage

    spiChannel.close() 

    time.sleep(0.1)

    # ftprint.PrintDoubleSpaceLine("*** Stop testing MCP3208 ***")


def TestMcp3208v01(): # v0.1 tlfong01 2013may27

    ftprint.PrintDoubleSpaceLine("*** Start testing MCP3208 ADC ***")   

    spiGuzuntyPi = spidev.SpiDev() 
    spiGuzuntyPi.open(0, 1)  

    controlTripleByteSingleEndChannel0 = [0x06, 0x00, 0x00]
    resultTripleByte = [0x00, 0x00, 0x00]
    resultTripleByte = spiGuzuntyPi.xfer2(controlTripleByteSingleEndChannel0) 

    ftprint.PrintEightBitPattern("ADC output byte 0 = ", resultTripleByte[0])
    ftprint.PrintEightBitPattern("ADC output byte 1 = ", resultTripleByte[1])
    ftprint.PrintEightBitPattern("ADC output byte 2 = ", resultTripleByte[2])

    resultDecimal =  (resultTripleByte[1] * (2 ** 8)) + (resultTripleByte[2])

    resultVoltage = (float(resultDecimal) / 4096) * 4.096 
    
    print "Analog voltage = ", resultVoltage

    spiGuzuntyPi.close() 

    ftprint.PrintDoubleSpaceLine("*** Stop testing MCP3208 ***") 

# *****************************************************************************
# Function - TestAdcMcp3201() 
# Description - 
# Sample call - 
# ***************************************************************************** 

def TestMcp320101(): #v1.3 tlfong01 2013may23

    ftprint.PrintDoubleSpaceLine("*** Start testing MCP3201 ADC ***")   

    spiGuzuntyPi = spidev.SpiDev() 
    spiGuzuntyPi.open(0, 1)  

    DummyDoubleByteList = [0x00, 0x00]
    adcOutputDoubleByteList = [0x55, 0x55]
    adcOutputDoubleByteList = spiGuzuntyPi.xfer2(DummyDoubleByteList) 

    ftprint.PrintEightBitPattern("ADC output byte 1 = ", adcOutputDoubleByteList[0])
    ftprint.PrintEightBitPattern("ADC output byte 2 = ", adcOutputDoubleByteList[1])

    adcDecimalValue = (adcOutputDoubleByteList[1] >> 1) + (adcOutputDoubleByteList[0] * (2 ** 7))

    # adcAnalogVoltage = (float(adcDecimalValue) / 4096) * 4.10 # without half voltage divider
    adcAnalogVoltage = ((float(adcDecimalValue) / 4096) * 4.10) * 2 # with half voltage divider
    
    print "Analog voltage = ", adcAnalogVoltage

    spiGuzuntyPi.close() 

    ftprint.PrintDoubleSpaceLine("*** Stop testing MCP3201 ***") 

# ***************************************************************************** 
# Function - TestAdcMcp3201() 
# Description - 
# Sample call - 
# Sample output -
# *** Start testing MCP3201 ADC ***
# ADC output byte 1 =  00001011
# ADC output byte 2 =  11111111
# Analog voltage   3.07299804687
# *** Stop testing MCP3201 ***
# ***************************************************************************** 

def TestMcp320102(spiChannel):

    ftprint.PrintDoubleSpaceLine("*** Start testing MCP3201 ADC ***")   

    DummyDoubleByteList = [0x00, 0x00]
    adcOutputDoubleByteList = [0x55, 0x55]
    adcOutputDoubleByteList = spiChannel.xfer2(DummyDoubleByteList) 

    ftprint.PrintEightBitPattern("ADC output byte 1 = ", adcOutputDoubleByteList[0])
    ftprint.PrintEightBitPattern("ADC output byte 2 = ", adcOutputDoubleByteList[1])

    adcDecimalValue = (adcOutputDoubleByteList[1] >> 1) + (adcOutputDoubleByteList[0] * (2 ** 7))

    # adcAnalogVoltage = (float(adcDecimalValue) / 4096) * 4.10 # without half voltage divider
    adcAnalogVoltage = ((float(adcDecimalValue) / 4096) * 4.10) * 2 # with half voltage divider
    
    print "Analog voltage = ", adcAnalogVoltage

    ftprint.PrintDoubleSpaceLine("*** Stop testing MCP3201 ***") 


def TestMcp320103(spiChannel, testTime, testCount):

    ftprint.PrintDoubleSpaceLine("*** Start testing MCP3201 ADC ***")   

    for i in range(testCount):
        DummyDoubleByteList = [0x00, 0x00]
        adcOutputDoubleByteList = [0x55, 0x55]
        adcOutputDoubleByteList = spiChannel.xfer2(DummyDoubleByteList) 
time.sleep(testTime)

    ftprint.PrintEightBitPattern("ADC output byte 1 = ", adcOutputDoubleByteList[0])
    ftprint.PrintEightBitPattern("ADC output byte 2 = ", adcOutputDoubleByteList[1])

    adcDecimalValue = (adcOutputDoubleByteList[1] >> 1) + (adcOutputDoubleByteList[0] * (2 ** 7))

    # adcAnalogVoltage = (float(adcDecimalValue) / 4096) * 4.10 # without half voltage divider
    adcAnalogVoltage = ((float(adcDecimalValue) / 4096) * 4.10) * 2 # with half voltage divider
    
    print "Analog voltage = ", adcAnalogVoltage

    ftprint.PrintDoubleSpaceLine("*** Stop testing MCP3201 ***") 


# .END

# fongtoy v1.26 tlfong01 2013may28

ProgramTitle = "FongToy v1.26 tlfong01 2013may28"

import sys 

import time 

import smbus 

import pdb 

import spidev 

import wiringpi

import wiringpi2

import RPIO as GPIO  

from RPIO import PWM 

from enum import Enum 

from subprocess import call

import ftgpio

import ftprint

import ftspi

import ftiox

import fteeprom

import ftguzuntypi

import ftdemux

import fttest

import ftadc

# *** Main program ***

# *** Start program message ***

ftprint.StartProgram(ProgramTitle)

# *** Troubleshooting functions ***

# *** GPIO tests v1.3 tlfong01 2013may23 ***

# ftgpio.TestLed()

# ftgpio.TestBuzzer()

# ftgpio.TestButtonEchoBuzzer()

# ftgpio.TestButtonEchoLed()

# *** SPI Tests v1.3 tlfong01 2013may23 ***

# ftspi.TestSpiLoopBack(spiChannelNumber = 0, spiChipEnableNumber = 1, testDataByte = 0x55, testCount = 1000, testTime = 0.001)

# ftiox.TestMcp23s17BlinkLed(spiChannelNumber = 0, spiChipEnableNumber = 0, spiChipSubAddress = 0)

# fteeprom.TestWriteReadEepormDataByte(spiChannelNumber = 0, spiChipEnableNumber = 1, startAddress = 0x0410, testDataByte = 0x55)

# ftguzuntypi.TestGuzuntyPi4digit7segmentLedModule(spiChannelNumber = 0, spiChipEnableNumber = 1)

# ftdemux.TestSelectSpiSlaveDevice(spiChannelNumber = 0, spiChipEnableNumber = 0, spiIoxSubAddress = 0, spiSlaveDeviceNumber = 5)

# fttest.TestDemuxEeprom(mcp23s17SubAddress = 0, eepromDemuxAddress = 2, testStartAddress = 0x0123, testWriteDataByte = 0x5a)

# fttest.TestDemuxEeprom(mcp23s17SubAddress = 0, eepromDemuxAddress = 1, testStartAddress = 0x0123, testWriteDataByte = 0x3b)

# fttest.TestDemuxEeprom(mcp23s17SubAddress = 0, eepromDemuxAddress = 0, testStartAddress = 0x0123, testWriteDataByte = 0x3b)

# *** Current test functions ***

# ftiox.TestMcp23s17BlinkLed(spiChannelNumber = 0, spiChipEnableNumber = 0, spiChipSubAddress = 0)

# ftdemux.TestSelectSpiSlaveDevice(spiChannelNumber = 0, spiChipEnableNumber = 0, spiIoxSubAddress = 0, spiSlaveDeviceNumber = 5)

# fttest.TestDemuxEeprom(mcp23s17SubAddress = 0, eepromDemuxAddress = 0, testStartAddress = 0x0123, testWriteDataByte = 0x3b)

# fttest.TestDemuxEeprom(mcp23s17SubAddress = 0, eepromDemuxAddress = 1, testStartAddress = 0x0411, testWriteDataByte = 0x4c)

# fttest.TestDemuxGuzuntyClock(mcp23s17SubAddress = 0, guzuntyClockDemuxAddress = 2, secondCount = 10)

# fttest.TestMcp320103(testTime = 0.1, testCount = 10)

# fttest.TestMcp320103(testTime = 0.01, testCount = 100)

# fttest.TestMcp320103(testTime = 0.05, testCount = 50)

# fttest.TestMcp320103(testTime = 0.1, testCount = 1)

# ftspi.TestSpiLoopBackV01(spiChannelNumber = 0, spiChipEnableNumber = 1, testDataByte = 0x55, testTime = 0.001, testCount = 60000)

# ftadc.TestMcp320101()

# ftadc.TestMcp3208v01()

# ftadc.TestMcp3208v02(inputMode = 1, channelNumber = 0) 

ftadc.TestMcp3208v03() 

# *** Stop program message ***

ftprint.StopProgram()

#.END

.END