' A PID controller using the Hitachi HD44780 LCD controller chip in 4-bit mode

Const HD44780_DB3 As Byte = 9  'Most significant bit
Const HD44780_DB2 As Byte = 10
Const HD44780_DB1 As Byte = 11
Const HD44780_DB0 As Byte = 12 'Least significant bit

Const HD44780_ENABLE As Byte = 13 'to pin 6
'Const HD44780_READWRITE As Byte = 14 '1=Read 0=Write, unused so tied to ground
Const HD44780_REGSELECT As Byte = 15 '1=Data 0=Instruction, to pin 4

Const LCDREAD As Byte = 1
Const LCDWRITE As Byte = 0
Const LCDDATA As Byte = 1
Const LCDINSTRUCTION As Byte = 0

Const INPUT_MODE As Byte = 5 'to Pin 5
Const INPUT_UP As Byte = 6 'to Pin 6
Const INPUT_DOWN As Byte = 7 'to Pin 7
Const INPUT_COMMIT As Byte = 8 'to Pin 8

Const TEMPERATURE_IN As Byte = 20 'to Pin 20

Dim sTemperatureActual As Single
Dim sTemperatureActualLast As Single
Dim sTemperatureSetpoint As Single

Dim sHeatProportion As Single
Dim sHeatIntegral As Single
Dim sHeatDerivative As Single

Dim sCoolProportion As Single
Dim sCoolIntegral As Single
Dim sCoolDerivative As Single

Dim bWorkingDisplay As Boolean
Dim sTmpString As String 'used for LCDPrintString

Dim TaskStack(0 To 40) As Byte

Sub Main()
Dim iCount As Integer
Dim sTemp As Single

Delay (0.5) 'in case of rescue
Call PutPin(26,0) ' green led on

Call LCDInit()
Call PIDInit()

'CallTask "MyTask", TaskStack
Do 
	Call PIDModeDisplayWork ()
	Call PIDModeGetSettingsHeat ()
	Call PIDModeGetSettingsCool ()

'	Call PIDModeGetSettingsPeriodic1 ()
'	Call PIDModeGetSettingsPeriodic2 ()
'	Call PIDModeGetSettingsMenu ()
Loop While (sTemperatureSetpoint < 101.0)

Call PutPin(26,1) ' green led off
End Sub 'Main

Sub MyTask ()
	Dim nonDimVolts As Single
	Dim sTemp As Single
	Dim bCount As Byte

	Do While (True)
		sTemp = sTemperatureActual / 500.0
		For bCount = 1 to 10 
			Call GetADC(TEMPERATURE_IN, nonDimVolts)
			sTemp = sTemp + ((nonDimVolts - sTemp)/100.0) 'smooths value jumps
			Call Sleep (0.01)
		Next
		sTemperatureActualLast = sTemperatureActual
		sTemperatureActual = sTemp * 500.0
		sTemperatureActual = CSng(CLng(sTemperatureActual * 10.0))/10.0 'trunc 0.1

' Just to see that something is happening.  This will be removed when it all works
		Call PutPin(25,0) ' red led on
		Call Sleep (0.25)
		Call PutPin(25,1) ' red led off
		Call Sleep (0.25)
	Loop
End Sub

Sub GetCurrentTemperature ()
	Dim nonDimVolts As Single
	Dim sTemp As Single
	Dim bCount As Byte

	sTemp = sTemperatureActual / 500.0
	For bCount = 1 to 10 
		Call GetADC(TEMPERATURE_IN, nonDimVolts)
		sTemp = sTemp + ((nonDimVolts - sTemp)/100.0) 'smooths value jumps
		Call Sleep (0.01)
	Next
	sTemperatureActualLast = sTemperatureActual
	sTemperatureActual = sTemp * 500.0
	sTemperatureActual = CSng(CLng(sTemperatureActual * 10.0))/10.0 'trunc 0.1
End Sub

Function PIDGetButton () As Byte
	If GetPin(INPUT_UP) = 0 Then
		Call Sleep (0.1) 'debounce
		PIDGetButton = INPUT_UP
		Exit Function
	ElseIf GetPin(INPUT_DOWN) = 0 Then
		Call Sleep (0.1) 'debounce
		PIDGetButton = INPUT_DOWN
		Exit Function
	ElseIf GetPin(INPUT_COMMIT) = 0 Then
		Call Sleep (0.1) 'debounce
		PIDGetButton = INPUT_COMMIT
		Exit Function
	ElseIf GetPin(INPUT_MODE) = 0 Then
		Call Sleep (0.1) 'debounce
		PIDGetButton = INPUT_MODE
		Exit Function
	Else
		PIDGetButton = 0
		Exit Function
	End If
End Function

Sub PIDInit ()
	Call PutPin(INPUT_MODE, bxInputPullup) ' Pull-up
	Call PutPin(INPUT_UP, bxInputPullup) ' Pull-up
	Call PutPin(INPUT_DOWN, bxInputPullup) ' Pull-up
	Call PutPin(INPUT_COMMIT, bxInputPullup) ' Pull-up

	bWorkingDisplay = False
	Call GetADC(TEMPERATURE_IN, sTemperatureActual)
	sTemperatureActual = sTemperatureActual * 500.0
	sTemperatureActualLast = sTemperatureActual
	sTemperatureSetpoint = 1.0

	sHeatProportion = 2.0
	sHeatIntegral = 200.0
	sHeatDerivative = 100.0

	sCoolProportion = 300.0
	sCoolIntegral = 100.0
	sCoolDerivative = 10.0
End Sub

Sub PIDModeDisplayWork ()
	Call GetCurrentTemperature ()
	Call LCDClearDisplay ()
	Call LCDGotoRowCol(0,0)
	sTmpString = "Actual Temp:"
	Call LCDPrintString ()
	Call LCDGotoRowCol(0,12)
	Call LCDPrintValueField(sTemperatureActual, True, 6)
	Call LCDSendCharacter (bx11011111) 'degrees sign

	Call LCDGotoRowCol(1, 3)
	sTmpString = "Setpoint:"
	Call LCDPrintString ()
	Call LCDGotoRowCol(1,12)
	Call LCDPrintValueField(sTemperatureSetpoint, True, 6)
	Call LCDSendCharacter (bx11011111) 'degrees sign

	bWorkingDisplay = True
	Do
	Loop Until PIDFieldValueGet (sTemperatureSetpoint, 1, 12, 6, True) = INPUT_MODE
	bWorkingDisplay = False
End Sub 'PIDModeDisplayWork

Sub PIDModeGetSettingsHeat ()
	Call LCDClearDisplay ()
	Call LCDGotoRowCol(0,1)
	sTmpString = "[Heat PID]"
	Call LCDPrintString ()

	Call LCDGotoRowCol(0,14)
	sTmpString = "Prop:"
	Call LCDPrintString ()
	Call LCDGotoRowCol(0,19)
	Call LCDPrintValueField (sHeatProportion, False, 4)

	Call LCDGotoRowCol(1,1)
	sTmpString = "Int:"
	Call LCDPrintString ()
	Call LCDGotoRowCol(1,5)
	Call LCDPrintValueField (sHeatIntegral, False, 4)

	Call LCDGotoRowCol(1,13)
	sTmpString = "Deriv:"
	Call LCDPrintString ()
	Call LCDGotoRowCol(1,19)
	Call LCDPrintValueField (sHeatDerivative, False, 4)
Top:
	If PIDFieldValueGet (sHeatProportion, 0, 19, 4, False) = INPUT_MODE Then
		Exit Sub
	End If

	If PIDFieldValueGet (sHeatIntegral, 1, 5, 4, False) = INPUT_MODE Then
		Exit Sub
	End If

	If PIDFieldValueGet (sHeatDerivative, 1, 19, 4, False) = INPUT_MODE Then
		Exit Sub
	End If
	Goto Top
End Sub 'PIDModeGetSettingsHeat

Sub PIDModeGetSettingsCool ()
	Call LCDClearDisplay ()
	Call LCDGotoRowCol(0,1)
	sTmpString = "[Cool PID]"
	Call LCDPrintString ()

	Call LCDGotoRowCol(0,14)
	sTmpString = "Prop:"
	Call LCDPrintString ()
	Call LCDGotoRowCol(0,19)
	Call LCDPrintValueField (sCoolProportion, False, 4)

	Call LCDGotoRowCol(1,1)
	sTmpString = "Int:"
	Call LCDPrintString ()
	Call LCDGotoRowCol(1,5)
	Call LCDPrintValueField (sCoolIntegral, False, 4)

	Call LCDGotoRowCol(1,13)
	sTmpString = "Deriv:"
	Call LCDPrintString ()
	Call LCDGotoRowCol(1,19)
	Call LCDPrintValueField (sCoolDerivative, False, 4)
Top:
	If PIDFieldValueGet (sCoolProportion, 0, 19, 4, False) = INPUT_MODE Then
		Exit Sub
	End If

	If PIDFieldValueGet (sCoolIntegral, 1, 5, 4, False) = INPUT_MODE Then
		Exit Sub
	End If

	If PIDFieldValueGet (sCoolDerivative, 1, 19, 4, False) = INPUT_MODE Then
		Exit Sub
	End If
	GoTo Top
End Sub

Function PIDFieldValueGet ( ByRef sValue As Single, ByVal bRow As Byte, _
		ByVal bCol As Byte, ByVal bWidth As Byte, ByVal bDecimal As Boolean) As Byte
	Dim bInput As Byte
	Dim sTmp As Single
	Dim sIncrement As Single

	If bDecimal = True Then
		sIncrement = 0.1
	Else
		sIncrement = 1.0
	End If

	Call LCDGotoRowCol(bRow, bCol + bWidth)

	sTmp = sValue
	Do
	If (bWorkingDisplay = True) Then
		Call GetCurrentTemperature()
		If (sTemperatureActualLast <> sTemperatureActual) Then
			Call LCDGotoRowCol(0,12)
			Call LCDPrintValueField(sTemperatureActual, True, 6)
			Call LCDGotoRowCol(bRow, bCol + bWidth)
		End If		
	End If 'bWorkingDisplay
 
		bInput = PIDGetButton()
		Select Case bInput
			Case INPUT_UP
				sTmp = sTmp + sIncrement
			Case INPUT_DOWN
				sTmp = sTmp - sIncrement
			Case INPUT_COMMIT
				sValue = sTmp
				Call Sleep (0.2) 'debounce
			Case INPUT_MODE
				' do nothing - function will bailout anyway
		End Select 'bInput
		If (bInput = INPUT_UP) Or (bInput = INPUT_DOWN) Then
			Call LCDGotoRowCol(bRow, bCol)
			Call LCDPrintValueField (sTmp, bDecimal, bWidth)
		End If
	Loop While (bInput <> INPUT_COMMIT) And (bInput <> INPUT_MODE)
	PIDFieldValueGet = bInput
End Function

Sub LCDInit()
	Call PutPin(HD44780_ENABLE, bxOutputLow)
	Call PutPin(HD44780_REGSELECT, bxOutputLow)
	Call Sleep(0.050) 'for LCD chip startup

	Call LCDPut4Bits ( bx00110000 ) 'function set (assumes 8-bit at startup)
	Call PulseOut(HD44780_ENABLE, 0.00005, bxOutputHigh)
	Call Sleep(0.005)
	Call LCDPut4Bits ( bx00110000 ) 'function set (assumes 8-bit at startup)
	Call PulseOut(HD44780_ENABLE, 0.00005, bxOutputHigh)
	Call Sleep(0.00015)
	Call LCDPut4Bits ( bx00110000 ) 'function set (assumes 8-bit at startup)
	Call PulseOut(HD44780_ENABLE, 0.00005, bxOutputHigh)
	Call LCDPut4Bits ( bx00100000 ) 'Now actually sets to 4-bit mode
	Call PulseOut(HD44780_ENABLE, 0.00005, bxOutputHigh)

	Call LCDFunctionSet () 'sets the complete function set
	Call LCDDisplayOFF ()
	Call LCDClearDisplay ()
	Call LCDEntryModeSet ()
	Call LCDDisplayON ()
End Sub

Sub LCDFunctionSet8 () '8-bit, 2 lines, no-scroll, blinking cursor
	Call LCDSendCommand ( bx00111000 )
End Sub

Sub LCDFunctionSet () '4-bit, 2 lines, no-scroll, blinking cursor
	Call LCDSendCommand ( bx00101000 )
End Sub

Sub LCDDisplayON ()
	Call LCDSendCommand ( bx00001111 )
End Sub

Sub LCDDisplayOFF ()
	Call LCDSendCommand ( bx00001000 )
End Sub

Sub LCDEntryModeSet ()
	Call LCDSendCommand ( bx00000110 )
End Sub

Sub LCDClearDisplay ()
	Dim bMask As Byte
	Dim bCount As Byte
	Dim bByte As Byte

	Call PutPin(HD44780_REGSELECT, LCDINSTRUCTION)
	Call PutPin(HD44780_ENABLE, bxOutputLow)

	bByte = bx00000001
	bMask = bx10000000
	For bCount = 0 to 3 'Put most significant bits first
		Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
		bMask = bMask \ 2
	Next
	Call PulseOut(HD44780_ENABLE,0.00005, bxOutputHigh)
	For bCount = 0 to 3 'Send last 4 bits
		Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
		bMask = bMask \ 2
	Next
	Call PulseOut(HD44780_ENABLE,0.00005, bxOutputHigh)
	Call Sleep(0.0016) 'Clear Display needs more time
End Sub

Sub LCDReturnHome ()
	Call LCDSendCommand ( bx00000010 )
	Call Sleep(0.0016)
End Sub

' Left-pads bWidth string with spaces. 
Sub LCDPrintValueField(ByVal sSingle As Single, ByVal bDecimal As Boolean, ByVal bWidth As Byte)
	Dim bLength As Byte
	Dim sTmp As String

	If bDecimal = True Then
		sTmp = CStr(CLng(sSingle * 10.0))
	Else
		sTmp = CStr(CLng(sSingle))
	End If
	bLength = CByte(Len(sTmp))

	If bDecimal = True Then 
		bLength = bLength + 1 ' for decimal point
	End If

	Do While (bWidth - bLength) > 0 ' print right padding
		Call LCDSendCharacter( CByte(Asc(" ")) )
		bWidth = bWidth -1		
	Loop

	If bDecimal = True Then
		sTmpString = Mid(sTmp, 1, CInt(bLength - 2)) 
		Call LCDPrintString ()

		Call LCDSendCharacter( CByte(Asc(".")) )

		sTmpString = Mid(sTmp, CInt(bLength-1), 1) 
		Call LCDPrintString ()
	Else
		sTmpString = sTmp
		Call LCDPrintString ()
	End If
End Sub

' LCDPrintString prints global sTmpString instead of using stack
Sub LCDPrintString ()
	Dim bCount As Byte
	Dim bCharPos As Byte
	Dim bMask As Byte
	Dim bByte As Byte
	Dim sChar As String * 1

	Call PutPin(HD44780_REGSELECT, LCDDATA)
	Call PutPin(HD44780_ENABLE, bxOutputLow)

	For bCharPos = 1 To CByte(Len(sTmpString))
		sChar = Mid(sTmpString, CInt(bCharPos), 1)
		bByte = Asc(sChar)
		bMask = bx10000000
		For bCount = 0 to 3 'Put most significant bits first
			Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
			bMask = bMask \ 2
		Next
		Call PulseOut(HD44780_ENABLE,0.00005, bxOutputHigh)
		For bCount = 0 to 3 'Put next 4 bits
			Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
			bMask = bMask \ 2
		Next
		Call PulseOut(HD44780_ENABLE,0.00005, bxOutputHigh)
		Call Sleep(0.00005)
	Next
End Sub

Sub LCDGotoRowCol (ByVal bRow As Byte, ByVal bCol As Byte)
	Dim bMask As Byte
	Dim bCount As Byte
	Dim bByte As Byte

	Call PutPin(HD44780_REGSELECT, LCDINSTRUCTION)
	Call PutPin(HD44780_ENABLE, bxOutputLow)

	bByte = bx10000000 Or (bRow * 64 + bCol)
	bMask = bx10000000
	For bCount = 0 to 3 'Put most significant bits first
		Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
		bMask = bMask \ 2
	Next
	Call PulseOut(HD44780_ENABLE,0.00005, bxOutputHigh)
	For bCount = 0 to 3 'Put next 4 bits
		Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
		bMask = bMask \ 2
	Next
	Call PulseOut(HD44780_ENABLE,0.00005, bxOutputHigh)
	Call Sleep(0.00005)
End Sub

'Sub LCDSetDDRAMAddr (ByVal bAddr As Byte)
'	Call LCDSendCommand ( bx10000000 Or bAddr) 'bAddr is 7-bits
'End Sub

Sub LCDSendCommand (ByVal bByte As Byte)
	Dim bMask As Byte
	Dim bCount As Byte

	Call PutPin(HD44780_REGSELECT, LCDINSTRUCTION)
	Call PutPin(HD44780_ENABLE, bxOutputLow)

	bMask = bx10000000
	For bCount = 0 to 3 'Put most significant bits first
		Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
		bMask = bMask \ 2
	Next
	Call PulseOut(HD44780_ENABLE,0.00005, bxOutputHigh)
	For bCount = 0 to 3 'Put most significant bits first
		Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
		bMask = bMask \ 2
	Next
	Call PulseOut(HD44780_ENABLE,0.00005, bxOutputHigh)
	Call Sleep(0.00005)
End Sub

Sub LCDSendCharacter (ByVal bByte As Byte)
	Dim bMask As Byte
	Dim bCount As Byte

	Call PutPin(HD44780_REGSELECT, LCDDATA)
	Call PutPin(HD44780_ENABLE, bxOutputLow)

	bMask = bx10000000
	For bCount = 0 to 3 'Put most significant bits first
		Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
		bMask = bMask \ 2
	Next
	Call PulseOut(HD44780_ENABLE,0.00005, bxOutputHigh)
	For bCount = 0 to 3 'Put next 4 bits
		Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
		bMask = bMask \ 2
	Next
	Call PulseOut(HD44780_ENABLE,0.00005, bxOutputHigh)
	Call Sleep(0.00005)
End Sub

' 4-bit interface - ENABLE pulse expects WRITE mode 
Sub LCDPutByte (ByVal bByte As Byte)
	Dim bMask As Byte
	Dim bCount As Byte
	
	bMask = bx10000000
	For bCount = 0 to 3 'Put most significant bits first
		Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
		bMask = bMask \ 2
	Next
	Call PulseOut(HD44780_ENABLE,0.00005, bxOutputHigh)
	For bCount = 0 to 3 'Put most significant bits first
		Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
		bMask = bMask \ 2
	Next
End Sub 

Sub LCDPut4Bits (ByVal bByte As Byte) 'msb's only
	Dim bMask As Byte
	Dim bCount As Byte
	
	bMask = bx10000000
	For bCount = 0 to 3 'Put most significant bits first
		Call PutPin(HD44780_DB3 + bCount, ((bByte And bMask)\bMask))
		bMask = bMask \ 2
	Next
End Sub