LCD Bargraph (fuel gauge)

'****************************************************************
'*  Name    : TEST1.BAS                                         *
'*  Author  : Karen                                             *
'*  Notice  : Copyright (c) 2008   .                            *
'*  Date    : 09/04/2008                                        *
'*  Version : 1.0                                               *
'*  Notes   :Program for Auto switching Diesel/Veg Oil on my car*
'*          :                                                   *
'****************************************************************
                    
' 
Define	LOADER_USED	1
@    __CONFIG _HS_OSC & _LVP_OFF
' Define various stuff
  DEFINE OSC 8
  DEFINE LCD_DREG PORTB       ' Set LCD Data port
        DEFINE LCD_DBIT 0           ' Set starting Data bit (0 or 4) if 4-bit bus .7
        DEFINE LCD_RSREG PORTB      ' Set LCD Register Select port
        DEFINE LCD_RSBIT 4          ' Set LCD Register Select bit 
        DEFINE LCD_EREG PORTB       ' Set LCD Enable port
        DEFINE LCD_EBIT 5           ' Set LCD Enable bit i.e, PORTE.4
        DEFINE LCD_BITS 4           ' Set LCD bus size ot 4 bit Upper Nibble (4 or 8 bits)
        DEFINE LCD_LINES 2         ' Set number of lines on LCD to 4 Lines
        DEFINE LCD_COMMANDUS 2000   ' Set command delay time in us
        DEFINE LCD_DATAUS 50        ' Set data delay time in us
        TRISC.1 = 1
       
        INPUT PORTC
       


' Allocate variables
command var     byte            ' Storage for command
i       var     byte            ' Storage for loop counter
temp    var     word            ' Storage for temperature
DQ      var     PORTA.5         ' Alias DS1820 data pin
DQ_DIR  var     TRISA.5         ' Alias DS1820 data direction pin


        ADCON1 = 7              ' Set PORTA and PORTE to digital

        Low PORTE.2             ' LCD R/W line low (W)
        Pause 100               ' Wait for LCD to start
        Lcdout $FE,1,"     DIESEL", $FE,$C0, "  Please Wait"      ' Display sign-on message
        Pause 3000
       


' Mainloop to read the temperature and display on LCD
mainloop:
      
        Gosub init1820          ' Init the DS1820

        command = $cc           ' Issue Skip ROM command
        Gosub write1820

        command = $44           ' Start temperature conversion
        Gosub write1820

        Pause 100              ' Wait 0.1 seconds for conversion to complete

        Gosub init1820          ' Do another init

        command = $cc           ' Issue Skip ROM command
        Gosub write1820

        command = $be           ' Read the temperature
        Gosub write1820
        Gosub read1820

        ' Display the decimal temperature
       
       IF PORTC.0 = 0 AND PORTC.3 = 0 then lcdout $FE,1,"     Diesel", $FE,$C0,"Temp", $fe, $C7, dec (temp >> 1), ".", dec (temp.0 * 5), $DF, "C":  LOW PORTE.0: LOW PORTE.1
       IF PORTC.0 = 1 AND PORTC.3 = 0 then gosub Tempcheck
       IF PORTC.0 = 0 AND PORTC.3 = 1 then gosub Tempcheck
       If PORTC.0 = 1 AND PORTC.3 = 1 then gosub Oil
       IF PORTD.1 = 1 then gosub Purging
        
       
Goto mainloop           ' Do it forever



Tempcheck:
lcdout $FE,1,"    TEMP LOW", $FE,$C0,"Still on  DIESEL"
LOW PORTE.0: LOW PORTE.1      
 return
 
Purging:

LCDOUT $FE,1," PURGING Please",$FE,$C0,"      WAIT"
HIGH PORTE.0
LOW PORTE.1

Pause 10000
         gosub Stop1 

Goto mainloop
 
Stop1:
LOW PORTE.0
LOW PORTE.1
LOW PORTD.1
LCDOUT $FE,1,"    Turn OFF",$FE,$C0,"   Engine NOW" 
while PORTD.1=0           'Give driver chance to turn engine off or wait for button to be pressed again
wend
pause 1000                 'so a very quick button press is NOT recognised and the program stays paused
Goto Tempcheck 

OIL:
LCDOUT $FE,1,"     Veg-Oil", $FE,$C0,"Temp", $fe, $C7, dec (temp >> 1), ".", dec (temp.0 * 5), $DF, "C"
HIGH PORTE.0
HIGH PORTE.1
return 


' Initialize DS1820 and check for presence
init1820:
        Low DQ                  ' Set the data pin low to init
        Pauseus 500             ' Wait > 480us
        DQ_DIR = 1              ' Release data pin (set to input for high)

        Pauseus 100             ' Wait > 60us
        If DQ = 1 Then
                Lcdout $fe, 1, "DS1820 not present"
                Pause 500
                Goto mainloop   ' Try again
        Endif
        Pauseus 400             ' Wait for end of presence pulse
        Return


' Write "command" byte to the DS1820
write1820:
        For i = 1 to 8          ' 8 bits to a byte
                If command.0 = 0 Then
                        Gosub write0    ' Write a 0 bit
                Else
                        Gosub write1    ' Write a 1 bit
                Endif
                command = command >> 1  ' Shift to next bit
        Next i
        Return

' Write a 0 bit to the DS1820
write0:
        Low DQ
        Pauseus 60              ' Low for > 60us for 0
        DQ_DIR = 1              ' Release data pin (set to input for high)
        Return

' Write a 1 bit to the DS1820
write1:
        Low DQ                  ' Low for < 15us for 1
@       nop                     ' Delay 1us at 4MHz
        DQ_DIR = 1              ' Release data pin (set to input for high)
        Pauseus 60              ' Use up rest of time slot
        Return


' Read temperature from the DS1820
read1820:
        For i = 1 to 16         ' 16 bits to a word
                temp = temp >> 1        ' Shift down bits
                Gosub readbit   ' Get the bit to the top of temp
        Next i
        Return

' Read a bit from the DS1820
readbit:
        temp.15 = 1             ' Preset read bit to 1
        Low DQ                  ' Start the time slot
@       nop                     ' Delay 1us at 4MHz
        DQ_DIR = 1              ' Release data pin (set to input for high)
        If DQ = 0 Then
                temp.15 = 0     ' Set bit to 0
        Endif
        Pauseus 60              ' Wait out rest of time slot
        Return

        End