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Sunday, January 13, 2013

MCP23008 IO Expander - Interrupt control


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Now I am updating the documentation for the interruptable keypad.  The program below handles both polling and interruptable (using MCP23008 INT, actually) keypad.


# *****************************************************************************
# tkp60.py - 2013jan13
# Author   - tlfong01
http://tlfong01.blogspot.hk/
# Raspberry Pi (Bv2) ,Raspbian Wheezy, Python 2.7.3, GPIO 0.4.1a
# *****************************************************************************

# *****************************************************************************
# License  - GNU GPLv3
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
# more details.
# You should have received a copy of the GNU General Public License along
# with this program. If not, see
http://www.gnu.org/licenses/.
# *****************************************************************************

# *** Import Python modules ***
import smbus
import sys
import RPi.GPIO as GPIO
from time import sleep
import select # interrupt module, not tested yet

# *****************************************************************************
# * Rpi GPIO pin assignments for LED, buzzer, and button *
GPIO.setmode(GPIO.BOARD) # Use RPi GPIO numbering, Not BCM numbering
GPIO.setwarnings(False)  # Disable linux's "pin already in use warning"

# RPi GPIO pin numbering *
# P1-02 5V, P1-04 5V, P1-06 Gnd
# P1-01 3V3, P1-03 I2C SDA1, P1-05 I2C SCL1
# P1-08 UART TxD (MCP23017 Reset)
# P1-10 UART RxD (MCP23017 INTB)
# P1-12 RPi GPIO_GEN1 (BCM18) LED (P1-12 > LED > 330R > Gnd)
# P1-14 Gnd
# P1-16 GPIO_GEN4 - Buzzer, 3V3 5mA (P1-16 > Buzzer > Gnd)
# P1-18 GPIO_GEN5 Button (3V3 > 10K > Contact 1/2 > 330R > Gnd)
# P1-20 Gnd
# P1-22 GPIO_GEN6 - MCP23008 INT / MCP23017 INTA  

RPiGPIOgen1 = 12 # Brown  (P1-12, BCM GPIO 18) LED
RPiGPIOgen4 = 16 # Yellow (P1-16, BCM GPIO 23) Buzzer
RPiGPIOgen5 = 18 # Green  (P1-18, BCM GPIO 24) Button
RPiGPIOgen6 = 22 # Blue   (P1-22, BCM GPIO 25) IOx/keypad interrupt

RPiTxD = 8 # Orange (P1-08) UART TxD
RPiRxD = 10 # Yellow (P1-10) UART RxD

# * GPIO device pins assignment *
LEDpin = RPiGPIOgen1
BuzzerPin = RPiGPIOgen4
ButtonPin = RPiGPIOgen5
TxDpin = RPiTxD
RxDpin = RPiRxD
KeypadInterruptPin = ButtonPin

# * GPIO pins list *

OutputPinList = [LEDpin, BuzzerPin, TxDpin]
InputPinWithNoPullUpList = [ButtonPin, KeypadInterruptPin, RPiGPIOgen6]
InputPinWithPullUpList = []

# *****************************************************************************
# * Global constants *
# * Loop counters *
TwoTimes = 2
FourTimes = 4
EightTimes = 8
TenTimes = 10
TwentyTimes = 20
FiftyTimes = 50
OneHundredTimes = 100
TwoHundredTimess = 200
FourHundredTimes = 400

# * Elapse times *
TwentyMilliSeconds = 0.02
FiftyMilliSeconds = 0.05
TenthSecond = 0.1
QuarterSecond = 0.25
HalfSecond = 0.5
OneSecond = 1
OneAndHalfSeconds = 1.5
TwoSeconds = 2

OnTime = TenthSecond
OffTime = QuarterSecond
ButtonDebouncingTime = QuarterSecond
TestTime = FiftyMilliSeconds

# * Nibble naming *
LowNibble = 0
HighNibble = 1
BothNibble = 2 # full byte of 8 bits

# * Nibble constants *
HighNibble1LowNibble0 = 0xf0
HighNibble0LowNibble1 = 0x0f

# * LED and buzzer states *
Off = False
On = True

# * Button states *
ButtonPressed = False
ButonReleased = True

# * Interrupt states *
Low = False
High = True

# *****************************************************************************
# * GPIO functions *
# 5V0 max = 50 mA, 3V3 max = 300 mA, GPIO per pin max = 17mA source, 12mA sink
setupOutputPin = lambda oPin: GPIO.setup(oPin, GPIO.OUT) # set GPIO pin as output
setupInputPinWithNoPullUp = lambda iPin: GPIO.setup(iPin, GPIO.IN, pull_up_down=GPIO.PUD_OFF) # set GPIO pin as input, no pull up
setupInputPinWithPullUp = lambda iPin: GPIO.setup(iPin, GPIO.IN, pull_up_down=GPIO.PUD_UP) # set GPIO pin as input, with pull up
writeOutputPin = lambda oPin, oValue: GPIO.output(oPin, oValue) # write value to output pin
setupWriteOutputPin = lambda oPin, oValue: (setupOutputPin(oPin), writeOutputPin(oPin, oValue)) # set and write
readInputPin = lambda iPin: GPIO.input(ButtonPin) # read value from input pin
def SetupGPIOpins(outputPinList, inputPinWithNoPullUpList, inputPinWithPullUpList): # set up GPIO pins in InputPinList and OutputPinList
    for oPin in outputPinList:
       setupWriteOutputPin(oPin, Off)
    for iPin in inputPinWithNoPullUpList:
        setupInputPinWithPullUp(iPin)
    for iPin in inputPinWithPullUpList:
        setupInputPinWithPullUp(iPin)

def SetupGPIO(): # set up GPIO pins
     SetupGPIOpins(OutputPinList, InputPinWithNoPullUpList, InputPinWithPullUpList )

# * pulse and echo functions *
def pulsePin(oPin, onTime, offTime): # blink LED or beep buzzer
    writeOutputPin(oPin, On)
    sleep(onTime)
    writeOutputPin(oPin, Off)   
    sleep(offTime)

def echoPin(iPin, oPin): # echo input pin to output pin, e.g. button to LED or buzzer
    while True:
        if readInputPin(iPin) == ButonReleased:
            pass
        else:
            pulsePin(oPin, OnTime, OffTime)
            break
        continue

def togglePin(oPin, toggleTime): # toggle pin
    writeOutputPin(oPin, On)
    sleep(toggleTime)
    writeOutputPin(oPin, Off)   
    sleep(toggleTime)

# * Test Buzzer, LED, Button functions *
def TestBuzzer(): # beep 4 times
    SetupGPIO()
    for i in range (FourTimes):
        pulsePin(BuzzerPin, OnTime, OffTime)

def TestLED(): # blink 8 times
    SetupGPIO()
    for i in range (EightTimes):
        pulsePin(LEDpin, OnTime, OffTime)

def TestButtonEchoBuzzer(): #
    SetupGPIO()
    for i in range (TenTimes):
        echoPin(ButtonPin, BuzzerPin)         

def TestButtonEchoLED(): #
    SetupGPIO()
    for i in range (TenTimes):
        echoPin(ButtonPin, LEDpin)

def TestToggleTxDpin():
    while True:
        togglePin(TxDpin, TwoSeconds)


# GPIO Interrupt function !!! not yet tested !!!
def TestInterruptPinFallingEdgeDetection(): # !!! Not tested !!!
    GPIO.cleanup() # set all input pins no pull up, disable all interutp detection setting
    SetupGPIO()  
    GPIO.set_low_event(InterruptPin) # set up low level detection

    for i in range(30):
        if GPIO.event_detected(InterruptPin):
     break
        else:
            print "No interrupt detected.", i
            sleep(1)
     continue

    GPIO.set_low_event(InterruptPin, enable = False)  # disable detection
    print "End of test, or interrupt detected"

# *****************************************************************************
#  * Beep functions *
OnTime = 0.1
OffTime = 0.25

def Beep(count):
    for i in range(count):
        pulsePin(BuzzerPin, OnTime, OffTime)
   
def StartBeep():
    Beep(4)
    sleep(1)

def EndBeep():
    Beep(4)

def OneBeep():
    Beep(1)

def FourBeeps():
    Beep(4)

# *****************************************************************************
# * MCP23008 / MCP23017 IO Expander *
# * References *
# 1. Mcirochip MCP23008/MCP23017 datasheet
# 2. Microchip Application Notes AN1081 (Matrix Keypad), AN1043 (GPIO Expander)

# * i2cdetect/i2cset commands *
# To detect I2C device base addresses
# sudo i2cdetect -y 1

# * To toggle GPIO pin *
#!/bin/bash
# i2cset -y 1 0x20 0x00 0x00
# count=0
# while [ $count -lt 10 ];
# do
#  i2cset -y 1 0x20 0x0a 0x00
#  sleep 0.5
#  i2cset -y 1 0x20 0x0a 0xff
#  sleep 0.5
#  let count++
# done

# To run i2c-X commands in user mode: sudo chmod 666 /dev/i2c-X
# sudo chmod 666 /dev/i2c-1

# * Setup SMBus *
I2C_BUS_NUMBER = 1 # P1-03 = SDA1, P1-05 = SCL1
smBus1 = smbus.SMBus(I2C_BUS_NUMBER) # global variable, cannot be set by a function

# * Register base addresses *
MCP23017BaseAddress1 = 0x22 # 1 LED, 1 button
MCP23008BaseAddress1 = 0x24 # 2 unipolar stepping motors
MCP23008BaseAddress2 = 0x25 # 1 decimal keypad

# * Port type *
PortA = 0
PortB = 1

# * Data bytes *
AllOutput = 0x00
AllHigh = 0xff
AllLow =  0x00
AlternateHighLow = 0xaa
AlternateLowHigh = 0x55

# * Direction setting bytes *
HalfHighHalfLow = 0xf0
HalfLowHalfHigh = 0x0f
Nibble1HighNibble2Low = 0xf0
Nibble1LowNibble2High = 0x0f

HighNibbleInputLowNibbleOutput = 0xf0
# * MCP23008/MCP23017 register address offsets *
InputOutputDirection = 0
InputPolarity = 1
InterruptOnChangeEnable = 2
InterruptOnChangeDefaultValue = 3
InterruptOnChangeMode = 4
Configuration = 5
PushPullOpenDrain = 6
InterruptFlag = 7
InterruptCapture = 8
PortStatus = 9
OutputLatch = 10

# * MCP23008/MCP23017 Band0/Band1 register address offset arrays *
RegisterAddressOffsetArray0 = [0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a,          
     0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a]
              
RegisterAddressOffsetArray1 = [0x00, 0x02, 0x04, 0x06, 0x08, 0x0a, 0x11, 0x13, 0x15, 0x17, 0x19,          
     0x01, 0x03, 0x05, 0x07, 0x09, 0x10, 0x12, 0x14, 0x16, 0x18, 0x1a]

# * Setup MCP23008/MCP23017 ports all output *
def SetupMCP23008PortAllOutput(registerBaseAddress):
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, InputOutputDirection, PortA, AllOutput)

def SetupMCP23017BothPortAllOutput(registerBaseAddress):
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, InputOutputDirection, PortA, AllOutput)
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, InputOutputDirection, PortB, AllOutput)

# * Write/Read MCP23008/MCP23017 registers *
def WriteDataByte(registerBaseAddress, registerAddressArray, dataRegisterIndex, portType, dataByte):
    if (portType == PortA) | (portType == PortA):
       addressOffset = registerAddressArray[dataRegisterIndex]
    if (portType == PortB):
       addressOffset = registerAddressArray[dataRegisterIndex + 11]
    smBus1.write_byte_data(registerBaseAddress, addressOffset, dataByte)

def ReadDataByte(registerBaseAddress, registerAddressArray, dataRegisterIndex, portType):
    if (portType == PortA):
       addressOffset = registerAddressArray[dataRegisterIndex]
    if (portType == PortB):
       addressOffset = registerAddressArray[dataRegisterIndex + 11]
    dataByte = smBus1.read_byte_data(registerBaseAddress, addressOffset)
    return dataByte

def ReadUpperDataNibble(registerBaseAddress, registerAddressArray, dataRegisterIndex, portType):
    dataByte = ReadDataByte(registerBaseAddress, registerAddressArray, dataRegisterIndex, portType)
    upperDataNibble = dataByte >> 4
    return upperDataNibble

# * Test MCP23008/MCP23017 toggle port functions *
def ToggleMCP23008GP(registerBaseAddress, toggleTime, toggleCount):
    SetupMCP23008PortAllOutput(registerBaseAddress)
    for i in range(toggleCount):
        WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, OutputLatch, PortA, AllHigh)
 sleep(toggleTime)
        WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, OutputLatch, PortA, AllLow)
  sleep(toggleTime)

def ToggleMCP23017GP(registerBaseAddress, toggleTime, toggleCount):
    SetupMCP23017BothPortAllOutput(registerBaseAddress)
    for i in range(toggleCount):
        WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, OutputLatch, PortA, AllHigh)
        WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, OutputLatch, PortB, AllHigh)
 sleep(toggleTime)
        WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, OutputLatch, PortA, AllLow)
        WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, OutputLatch, PortB, AllLow)
  sleep(toggleTime)

def TestToggleMCP23008GP():
    ToggleTime = 0.5
    ToggleCount = 4
    ToggleMCP23008GP(MCP23008BaseAddress1, ToggleTime, ToggleCount)

def TestToggleMCP23017GP():
    ToggleTime = 0.5
    ToggleCount = 4
    ToggleMCP23008GP(MCP23017BaseAddress1,  ToggleTime, ToggleCount)

# * MCP23008/MCP23017 Interrupt functions *
# * MCP23008 Interrupt setting *
def EnableInterruptOnChangeHighNibble(registerBaseAddress):
    EnableInterruptHighNibble = 0xf0
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, InterruptOnChangeEnable, PortA, EnableInterruptHighNibble)

def DisableInterruptOnChangeHighNibble(registerBaseAddress):
    DisableInterruptHighNibble = 0x00
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, InterruptOnChangeEnable, PortA, DisableInterruptHighNibble)

def SetInterruptOnChangeDefaultHighNibble(registerBaseAddress):
    DefaultValueByte = 0xf0
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, InterruptOnChangeDefaultValue, PortA, DefaultValueByte)

def SetInterruptOnChangeCompareDefaultHighNibble(registerBaseAddress):
    InterruptOnChangeDefaultValueHighNibble = 0xf0 # GP4~7 change from default value will cause interrupt
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, InterruptOnChangeMode, PortA, InterruptOnChangeDefaultValueHighNibble)

def SetInterruptOutputPushPull(registerBaseAddress): # interrupt pin open drain, no auto add inc, no slew rate
    PushPull  = 0b00111010 # 0x32, seq/slew disabled, interrupt output drive drive (push pull) active High
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, PushPullOpenDrain, PortA, PushPull)

def SetInterruptOutputOpenDrain(registerBaseAddress): # interrupt pin open drain, no auto add inc, no slew rate
    OpenDrain = 0b00111000 # 0x34, seq/slew disabled, interrupt output open drain (don't care active High or Low)
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, PushPullOpenDrain, PortA, OpenDrain)

# * Port A Interrupt checking *
def ReadInterruptFlagHighNibble(registerBaseAddress):
    interruptFlagByte = ReadDataByte(registerBaseAddress,  RegisterAddressOffsetArray0, InterruptFlag, PortA) 
    interruptFlagNibble = interruptFlagByte >> 4
    return interruptFlagNibble  
   
def ReadInterruptCaptureHighNibble(registerBaseAddress):
    interruptCaptureByte = ReadDataByte(registerBaseAddress, RegisterAddressOffsetArray0, InterruptCapture, PortA)   
    interruptCaptureNibble = interruptCaptureByte >> 4
    return interruptCaptureNibble 

def ConvertIntegerToFourBitPattern(integer):
    FourBitPattern = [""]
    for k in range(4):
        FourBitPattern = [i+j for i in ['0','1'] for j in FourBitPattern]
    return FourBitPattern[integer]

def DetectOneInterrupt(registerBaseAddress):   
    interruptFlagNibble = ReadInterruptFlagHighNibble(registerBaseAddress)
    interruptCaptureNibble = ReadInterruptCaptureHighNibble(registerBaseAddress)
    print "Interrupt capture high nibble = ", ConvertIntegerToFourBitPattern(interruptCaptureNibble)
    print "Interrupt capture high nibble = ", ConvertIntegerToFourBitPattern(interruptCaptureNibble)
    ClearInterruptOnChangeHighNibble(registerBaseAddress) # !!! clear interrupt !!!
    sleep(2)

def TestDetectInterrupt(count):
    RegisterBaseAddress =  MCP23008BaseAddress2
    SetupKeypadInterruptHighNibbleCompareDefaultValueOpenDrainOutput(RegisterBaseAddress)
    for i in range(count):
        DetectOneInterrupt(RegisterBaseAddress)

# *****************************************************************************
# * Unipolar Stepping Motor 28BYJ48/NPM-PF35/PX245 *
# Unipolar Stepping Motor Switching Sequence
# 1. Wave sequence = 1 - 3 - 2 - 4 (A-, B-, A+, B+)
# 2. Full step sequence = 13 - 14 - 24 - 23 (A-B-, A-B+, A+B+, A+B-)
# 3. Half step sequence  = 13 - 1 - 14 - 4 - 24 - 2 - 23 - 3
# 4. One step swing = 1 - 3 - 1 - 3 (A-, B-, A-, B-)
# Winding        A-(1)    A+(2)    B-(3)   B+(4)    COM
# NPM PF35       Black    Yellow   Brown   Orange   Red
# 28BYJ48        Blue     Pink     Yellow  Orange   Red 
# PX245          Black    Green    Blue    Red      Yelow/White

# * Convert decimal pin number to hex *
def convert1PinToHex(p): # convert 1 of 8 high pin to hex
    hexString = 0x01
    for count in range(p-1):
    hexString = hexString << 1
    return hexString
def convert2PinToHex(p1, p2):  # convert 2 of 8 high pins to hex
    return (convert1PinToHex(p1) | convert1PinToHex(p2))

def convert2PinToHighNibble(p1, p2):  # convert 2 of 8 high pins to high nibble
    lowNibble = convert1PinToHex(p1) | convert1PinToHex(p2)
    highNibble = lowNibble << 4
    return highNibble

# * Move unipolar stepping motor *
def WriteMotorWindingWaveSequence1324(RegisterBaseAddress, NibbleType, StepCount, StepTime): # move motor using 13-24 sequence 
    # Set port all output
    WriteDataByte(MCP23008BaseAddress1, RegisterAddressOffsetArray0, InputOutputDirection, PortA, AllOutput)

    if NibbleType == LowNibble:
 hexString1 =  convert2PinToHex(1, 3)
   hexString2 =  convert2PinToHex(2, 4)
    else:
 hexString1 = convert2PinToHighNibble(1, 3)
 hexString2 = convert2PinToHighNibble(2, 4)
    for i in range(StepCount):
        WriteDataByte(MCP23008BaseAddress1, RegisterAddressOffsetArray0, OutputLatch, PortA, hexString1)
    sleep(StepTime)
        WriteDataByte(MCP23008BaseAddress1, RegisterAddressOffsetArray0, OutputLatch, PortA, hexString2)
        sleep(StepTime)

def WriteMotorWindingFullStepSequence13232414(RegisterBaseAddress, NibbleType, StepCount, StepTime): #move motor using 13-23-24-14 sequence
    # Set port all output
    WriteDataByte(MCP23008BaseAddress1, RegisterAddressOffsetArray0, InputOutputDirection, PortA, AllOutput)

    if NibbleType == LowNibble:
     motorWindingActivationPatternArray = (0x05, 0x06, 0x0a, 0x09)
    else:
 motorWindingActivationPatternArray = (0x50, 0x60, 0xa0, 0x90)
    for i in range(StepCount):
 for pattern in motorWindingActivationPatternArray:
            WriteDataByte(MCP23008BaseAddress1, RegisterAddressOffsetArray0, OutputLatch, PortA, pattern)
     sleep(StepTime)

def TestConvert1PinToHex(): # test convert 1 high pin to hex
    print "*** Testing 1 pin number decimal 0 ~ 7 converted to hexdecimal 0x01 ~ 0x80"
    for d in range(8):
    print hex(convert1PinToHex(d))

def TestConvert2PinToHex(p1, p2): # test convert 2 high pins to hex
    print "*** Testing 2 pin numbers decimal 0 ~ 7 converted to hexdecimal"
    print "Pin 1 = ", p1, "Pin 2 = ", p2
    print "Hex = ", hex(convert2PinToHex(p1, p2))

def TestConvert2PinToHighNibble(p1, p2): # test convert 2 of 8 high pins to high nibble
    print "*** Testing 2 pin numbers decimal 0 ~ 7 converted to high nibble"
    print "Pin 1 = ", p1, "Pin 2 = ", p2
    print "HighNibble = ", hex(convert2PinToHighNibble(p1, p2))

def MoveTwoMotors(RegisterBaseAddress): 
 OneBeep()
 WriteMotorWindingWaveSequence1324(MCP23008BaseAddress1, LowNibble, TwentyTimes, FiftyMilliSeconds)
 OneBeep()
 WriteMotorWindingWaveSequence1324(MCP23008BaseAddress1, HighNibble, TwentyTimes, FiftyMilliSeconds)
 # OneBeep()
 # WriteMotorWindingFullStepSequence13232414(MCP23008BaseAddress1, LowNibble, TwentyTimes, FiftyMilliSeconds)
 # OneBeep()
 # WriteMotorWindingFullStepSequence13232414(MCP23008BaseAddress1, HighNibble, TwentyTimes, FiftyMilliSeconds)

def TestMotor():
    MotorRegisterBaseAddress = MCP23008BaseAddress1
    MoveTwoMotors(MotorRegisterBaseAddress)

# *****************************************************************************
# * Decimal keypad *

# * Function descriptions *
# SetupKeypad(registerBaseAddress)
# Assign GP0~3 as output (Col0~2, Col3 n.c), GP4~7 input (Row0~3)

# WriteAllColumnsLow(registerBaseAddress)
# Set all column outputs (GP0~2 actually, GP3 dummy)

# LoopUntilGpioPortHighNibbleChange(registerBaseAddress)
# Loop until GPIO register's GP4~7 not all High (some key pressed)

# LoopUntilInterruptCaptureHighNibbleChange(registerBaseAddress)
# Loop until INTCAP register's ICP4~7 not all High (some key pressed)

# Keypad scanning procedure version 1.0
# 1. Set 3 column ports GP0, GP1, GP2 as output (GP3 don't care)
# 2. Set 4 row ports GP4, GP5, GP6, GP7 as input
# 3. Write Low to all column ports
# 4. Wait until any key pressed (pooling or interrupt)
# 5. Find rowNumber and column number
# 6. Calculate key number

# * keypad base address and smBus setting *
KeypadRegisterBaseAddress = MCP23008BaseAddress2
KeypadSmBus = smBus1

PollGpioRegister = 0
PollKeypadInterruptPin = 1

def SetupKeypad(registerBaseAddress):
    SetupKeypadGPIO(registerBaseAddress)
    SetupKeypadInterrupt(registerBaseAddress)
    ClearKeypadInterrupt(registerBaseAddress)

def SetupKeypadGPIO(registerBaseAddress):
    UpperNibbleInputLowerNibbleOutput = 0xf0 # (GP4~7, Row0~3) = input, lower nibble (GP0~3, Column0~2, 3 = no coonect) = output
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, InputOutputDirection, PortA, UpperNibbleInputLowerNibbleOutput)
    WriteAllColumnsLow(registerBaseAddress)

def SetupKeypadInterrupt(registerBaseAddress):
    EnableInterruptOnChangeHighNibble(registerBaseAddress) # Enable interrupt on upper nibble (GP4~7)
    SetInterruptOnChangeDefaultHighNibble(registerBaseAddress) # Interrupt default values = all high (GP4~7 0b1111)
    SetInterruptOnChangeCompareDefaultHighNibble(registerBaseAddress) # select compare default value interrutpt
    SetInterruptOutputOpenDrain(registerBaseAddress) # set interrupt output (INT) open drain

def ClearKeypadInterrupt(registerBaseAddress):
    WriteAllColumnsLow(registerBaseAddress)
    sleep(0.5)
    dummyRead = ReadInterruptCaptureHighNibble(registerBaseAddress)

def EnableInterruptOnChangeHighNibble(registerBaseAddress):
    EnableInterruptHighNibble = 0xf0
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, InterruptOnChangeEnable, PortA, EnableInterruptHighNibble)

def SetInterruptOnChangeDefaultHighNibble(registerBaseAddress):
    DefaultValueByte = 0xf0
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, InterruptOnChangeDefaultValue, PortA, DefaultValueByte)

def SetInterruptOnChangeCompareDefaultHighNibble(registerBaseAddress):
    InterruptOnChangeDefaultValueHighNibble = 0xf0 # GP4~7 change from default value will cause interrupt
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, InterruptOnChangeMode, PortA, InterruptOnChangeDefaultValueHighNibble)

def SetInterruptOutputPushPull(registerBaseAddress): # interrupt pin open drain, no auto add inc, no slew rate
    PushPull  = 0b00111010 # 0x32, seq/slew disabled, interrupt output drive drive (push pull) active High
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, PushPullOpenDrain, PortA, PushPull)

def SetInterruptOutputOpenDrain(registerBaseAddress): # interrupt pin open drain, no auto add inc, no slew rate
    OpenDrain = 0b00111000 # 0x34, seq/slew disabled, interrupt output open drain (don't care active High or Low)
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, PushPullOpenDrain, PortA, OpenDrain)

def WriteColumns(registerBaseAddress, columnDataNibble):
    columnDataByte = columnDataNibble | 0x00
    WriteDataByte(registerBaseAddress, RegisterAddressOffsetArray0, OutputLatch, PortA, columnDataByte)

def WriteAllColumnsLow(registerBaseAddress):
    AllColumnsLowNibble = 0x0
    WriteColumns(registerBaseAddress, AllColumnsLowNibble)

def WriteColumn0Low(registerBaseAddress):
    Column0LowNibble = 0xe
    WriteColumns(registerBaseAddress, Column0LowNibble)

def WriteColumn1Low(registerBaseAddress):
    Column1LowNibble = 0xd
    WriteColumns(registerBaseAddress, Column1LowNibble)

def WriteColumn2Low(registerBaseAddress):
    Column2LowNibble = 0xb
    WriteColumns(registerBaseAddress, Column2LowNibble)

def GetRowDataByte(registerBaseAddress):
    rowDataByte = ReadDataByte(registerBaseAddress, RegisterAddressOffsetArray0, PortStatus, PortA)
    return rowDataByte

def GetRowDataNibble(registerBaseAddress):
    rowDataByte = ReadDataByte(registerBaseAddress, RegisterAddressOffsetArray0, PortStatus, PortA)
    rowDataNibble = rowDataByte >> 4
    return rowDataNibble

def GetRowNumber(registerBaseAddress):
    rowDataByte = ReadDataByte(registerBaseAddress, RegisterAddressOffsetArray0, PortStatus, PortA)
    rowDataNibble = rowDataByte >> 4
    if rowDataNibble == 0b1110:
        rowNumber = 0
        return rowNumber
    elif rowDataNibble == 0b1101:
        rowNumber = 1
        return rowNumber
    elif rowDataNibble == 0b1011:
        rowNumber = 2
        return rowNumber
    elif rowDataNibble == 0b0111:
        rowNumber = 3
        return rowNumber
    else:
        rowNumber = 99 
 return rowNumber

def GetColumnNumber(registerBaseAddress):
    RowsAllHigh = 0xf

    WriteColumn0Low(registerBaseAddress)
    rowDataNibble = ReadUpperDataNibble(registerBaseAddress, RegisterAddressOffsetArray0, PortStatus, PortA)
    if rowDataNibble != RowsAllHigh:
        columnNumber = 0
        return columnNumber

    WriteColumn1Low(registerBaseAddress)
    rowDataNibble = ReadUpperDataNibble(registerBaseAddress, RegisterAddressOffsetArray0, PortStatus, PortA)
    if rowDataNibble != RowsAllHigh:
        columnNumber = 1
        return columnNumber

    WriteColumn2Low(registerBaseAddress)
    rowDataNibble = ReadUpperDataNibble(registerBaseAddress, RegisterAddressOffsetArray0, PortStatus, PortA)
    if rowDataNibble != RowsAllHigh:
        columnNumber = 2
        return columnNumber

def GetKeyNumber(rowNumber, columnNumber):
    print "Row Number = ", rowNumber
    print "Column Number = ", columnNumber
    keyNumber = (rowNumber * 3) + (columnNumber + 1)
    return keyNumber

def GetKey(registerBaseAddress, pollType):
    PollGpioRegister = 0
    PollKeypadInterruptPin = 1

    if (pollType == PollGpioRegister):
        print "Polling GpioRegister"
        LoopUntilGpioPortHighNibbleChange(registerBaseAddress)

    elif (pollType == PollKeypadInterruptPin):
        print "Polling Interrupt Pin"
        LoopUntilKeypadInterruptPinLow(registerBaseAddress, KeypadInterruptPin)        

    rowNumber = GetRowNumber(registerBaseAddress)
    columnNumber = GetColumnNumber(registerBaseAddress)
    keyNumber = GetKeyNumber(rowNumber, columnNumber)
    return keyNumber

def GetKeyString(registerBaseAddress, pollType, count):
    for i in range (count):       
        OneBeep()
 keyNumber = GetKey(registerBaseAddress, pollType)
        print "Key", i + 1, " = ", keyNumber

def LoopUntilGpioPortHighNibbleChange(registerBaseAddress):
    WriteAllColumnsLow(registerBaseAddress)
    NoKeyPressedNibble = 0xf
    rowDataNibble = NoKeyPressedNibble
    while (rowDataNibble == NoKeyPressedNibble):
        rowDataNibble = GetRowDataNibble(registerBaseAddress)
    sleep(0.05) # debouncing time 50mS

def LoopUntilKeypadInterruptPinLow(registerBaseAddress, interruptPin):
    ClearKeypadInterrupt(registerBaseAddress)
    interruptPinState = readInputPin(interruptPin)
    print "interruptPinState = ", interruptPinState
    while (interruptPinState == True):
       interruptPinState = readInputPin(interruptPin)
       #print "interruptPinState = ", interruptPinState
       #sleep(1)
    print "interruptPinState = ", interruptPinState
    sleep(0.05) # debouncing time 50mS

def TestKeypad(registerBaseAddress, pollType, count):
    SetupKeypad(registerBaseAddress)
    if (pollType == PollKeypadInterruptPin):
        SetupKeypadInterrupt(registerBaseAddress)
        ClearKeypadInterrupt(registerBaseAddress)
    print "\n** Start testing keypad. **" 
    print "Press keypad ", count, "times."
    GetKeyString(registerBaseAddress, pollType, count)
    ClearKeypadInterrupt(registerBaseAddress)
    print "** Stop testing keypad 2013jan13 **\n"

def ClearKeypadInterrupt(registerBaseAddress):
    WriteAllColumnsLow(registerBaseAddress)
    sleep(0.5)
    dummyRead = ReadInterruptCaptureHighNibble(registerBaseAddress) # to clear interrupt

def ReadKeypadInterruptPin(interruptPin):
    interruptStatus = readInputPin(interruptPin)
    return interruptStatus

# ****************************************************************************
# * Program messages *
def StartMessage(message):
    StartBeep()
    print message

def EndMessage(message):
    EndBeep()
    print message

# *****************************************************************************
# * Main test functions *
# * Setup RPi GPIO *
SetupGPIO()
StartMessage("\n*** Test Decimal Keypad - v6.0  TL Fong 2013jan12 ***")

# * Part 1 - Test RPi GPIO (buzzer, LED, button, TxDpin *
#TestBuzzer() # beep buzzer 4 times
#TestLED() # blink LED 8 tmes
#TestButtonEchoBuzzer() # echo buton with buzzer 10 times
#TestButtonEchoLED() # echo button with LED 10 times

#TestToggleTxDpin() # toggle TxD pin every 2 seconds
# * Part 2 - Test MCP23008/MCP23017 output ports *
# TestToggleMCP23008GP() # toggle MCP23008 output port
# TestToggleMCP23017GP() # toggle MCP23017 output ports

# * Part 3 - Test stepping motor *
# TestMotor() # move two stepping motors
# * Part 4 - Test decimal keypad *
TestKeypad(KeypadRegisterBaseAddress, PollGpioRegister, count = 4)
TestKeypad(KeypadRegisterBaseAddress, PollKeypadInterruptPin, count = 4)

EndMessage("\n*** End of program ***")
# *****************************************************************************
# End of Program
# *****************************************************************************

pi@raspberrypi ~/python_programs/test_basic $ sudo python tkp60.py
*** Test Decimal Keypad - v6.0  TL Fong 2013jan12 ***
** Start testing keypad. **
Press keypad  4 times.
Polling GpioRegister
Row Number =  0
Column Number =  0
Key 1  =  1
Polling GpioRegister
Row Number =  0
Column Number =  0
Key 2  =  1
Polling GpioRegister
Row Number =  1
Column Number =  0
Key 3  =  4
Polling GpioRegister
Row Number =  2
Column Number =  0
Key 4  =  7
** Stop testing keypad 2013jan13 **


** Start testing keypad. **
Press keypad  4 times.
Polling Interrupt Pin
interruptPinState =  True
interruptPinState =  False
Row Number =  0
Column Number =  0
Key 1  =  1
Polling Interrupt Pin
interruptPinState =  True
interruptPinState =  False
Row Number =  2
Column Number =  1
Key 2  =  8
Polling Interrupt Pin
interruptPinState =  True
interruptPinState =  False
Row Number =  2
Column Number =  2
Key 3  =  9
Polling Interrupt Pin
interruptPinState =  True
interruptPinState =  False
Row Number =  3
Column Number =  1
Key 4  =  11
** Stop testing keypad 2013jan13 **


*** End of program ***

.END

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