wrong positive and negative voltages on lcd 20x4

[josepic]

'Config for 16f886
#CONFIG
    __config _CONFIG1, _INTRC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_ON & _LVP_OFF & _CP_ON & _CPD_ON
#ENDCONFIG


include "fp2032.bas"    ' Include file for 14-bit core with RAM at $20 (32-bit)
define OSC  8
DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 4
DEFINE LCD_RSREG PORTC
DEFINE LCD_RSBIT 0
DEFINE LCD_EREG PORTC
DEFINE LCD_EBIT 1
DEFINE LCD_BITS 4
DEFINE LCD_LINES 2




DEFINE ADC_BITS 10
DEFINE ADC_CLOCK 3
DEFINE ADC_ SAMPLEUS 50
'********************************************************************
LED VAR PORTC.4
TXD VAR PORTC.6
B1 VAR WORD
B2 VAR WORD
VALOR1 VAR BYTE
VALOR2 VAR BYTE
fpplaces  var  byte     ' Used to define number of decimal places in fpdisplay,fpdisplayr
ahold    var   word     ' Required by fpdisplay
bhold    var   word     ' Required by fpdisplay
'********************************************************************
INICIO:
         TRISC.6 = 0          'in
         TRISC.7 = 1          'out
         TRISA = 255          'Port_A = in
         ADCON1 = %11000010   'left alignment
         TRISB.6 = 0          'out


         LCDOUT  $FE,2,"  FUENTE SIMETRICA  "     '1_line
         LCDOUT  $FE,$C0," JOSE LUIS COMAS LL "   '2_line
         LCDOUT  $FE,$94,"VOLT.NEGATIVO:-"        '3_line
         LCDOUT  $FE,$D4,"VOLT.POSITIVO:+"        '4_line
COMENZAR:
         ADCIN 1, B1    'read negativ via chanal_1_ADC
         ADCIN 2, B2    'read positiv via chanal_2_ADC

         'send ADC to terminal
         SEROUT2  TXD,188,["$", "$", DEC4 B1,"$", "$",DEC4 B2,10,13]

         aint = B1      'read -volt_to+B1
         gosub itofa    'Conviertelo a punto flotante
         bint = 2000    'Carga el valor 2000 (5*400)
         gosub itofb    'Conviertelo en punto flotante
         gosub  fpmul   'ADCres * 2000
         bint = 52224   'Carga el valor de la cuenta maxima del ADC * 51
         gosub itofb    'Conviertelo en punto flotante
         GOSUB  fpdiv   '(ADCres * 2000)/52224
'++++++++++++++
'pv         LCDOUT  $FE,$A3,"     "    'Limpia el espacio donde se coloca el voltaje negativo
         LCDOUT  $FE,$A3
'++++++++++++++
         fpplaces = 2 : Gosub fpdisplayr    ' Call display routine

         aint = B2      'Transfiere el valor del ADC del voltaje positivo
         gosub itofa    'Conviertelo a punto flotante
         bint = 35      'Carga el valor 35 (5*7)
         gosub itofb    'Conviertelo en punto flotante
         gosub  fpmul   'ADCres * 35
         bint = 1024    'Carga el valor de la cuenta maxima del ADC
         gosub itofb    'Conviertelo en punto flotante
         GOSUB  fpdiv   '(ADCres * 35)/1024
'++++++++++++++
'pv         LCDOUT  $FE,$E3,"     "    'Limpia el espacio donde se coloca el voltaje positivo
         LCDOUT  $FE,$E3
'++++++++++++++
         fpplaces = 2 : Gosub fpdisplayr    ' Call display routine


         HIGH LED
        GOTO COMENZAR

' The fpdisplayr routine checks for number of places, then adds the appropriate
' value to achieve rounding.  To save RAM space, the values are hard coded
' in floating point format.


fpdisplayr: If fpplaces=0 Then                  ' Set floating point barg to 0.5
                        bexp = $7E
                        bargb0 = $00
                        bargb1 = $00
                        bargb2 = $01
                  Endif
                  If fpplaces=1 Then                  ' Set floating point barg to 0.05
                        bexp = $7A
                        bargb0 = $4C
                        bargb1 = $CC
                        bargb2 = $CD
                  Endif
                  If fpplaces=2 Then                  ' Set floating point barg to 0.005
                        bexp = $77
                        bargb0 = $23
                        bargb1 = $D7
                        bargb2 = $0B
                  Endif
                  If fpplaces=3 Then                  ' Set floating point barg to 0.0005
                        bexp = $74
                        bargb0 = $03
                        bargb1 = $12
                        bargb2 = $6F
                  Endif
                  If fpplaces=4 Then                  ' Set floating point barg to 0.00005
                        bexp = $70
                        bargb0 = $51
                        bargb1 = $B7
                        bargb2 = $17
                  Endif


                  Gosub fpadd                         ' add barg to aarg
                  
' The fpdisplay routine outputs the signed value of aarg in decimal floating point format. It
' can display a positive value of 65535, and decimals to 4 places. The number of decimal
' places should be stored in fpplaces before calling the routine. The routine reads the
' floating point value of aarg. This value should NOT be converted to an integer before
' calling fpdisplay. The integer conversion will be perfomed as part of this routine, and
' aint will be returned to the calling program just as from the itofa routine.


fpdisplay:  bexp = aexp                         ' Store the FP value of aarg to the barg variables
                  bargb0 = aargb0
                  bargb1 = aargb1
                  bargb2 = aargb2


                  Gosub ftoia                   ' Convert aarg to integer
                  ahold = aint                        ' Save this value for the final display
                  
                  Gosub itofa                   ' Convert integer back to float


                  Swap aexp,bexp                      ' Swap the FP values of aarg and barg before subtraction
                  Swap aargb0,bargb0
                  Swap aargb1,bargb1
                  Swap aargb2,bargb2


                  Gosub fpsub                   ' Subtract the integer portion from the full number




                  bint = 10                     ' Make bint = 10 E fpplaces
                  If fpplaces=2 Then
                        bint = 100
                  Endif
                  If fpplaces=3 Then
                        bint = 1000
                  Endif
                  If fpplaces=4 Then
                        bint = 10000
                  Endif


                  bhold = bint                        ' Save the integer value of bint for zeros loop


                  Gosub itofb                   ' Convert bint to integer prior to FP multiply
                  Gosub fpmul                   ' Multiply the decimal portion x 10 E fpplaces


                  Gosub ftoia                   ' Convert result to aint integer


                  Lcdout dec ahold              ' Display integer portion
                  If fpplaces > 0 Then                            
                        Lcdout "."              ' Display decimal point
zeros:                  bhold = bhold / 10                                          ' Set bhold to be next place to right
                        If (aint < bhold) AND (bhold > 1) Then          ' Check for leading zero in decimal
                              Lcdout "0"                                            ' Display leading zero
                              Goto zeros                                            ' loop to check for another zero
                        Endif
                        Lcdout dec aint               ' Display the rest of the decimal portion
                  Endif


                  aint = ahold                        ' Restore the original value of aint


                  Return              
'pv         LCDOUT  $FE,$A3,"     "    'Limpia el espacio donde se coloca el voltaje negativo
'pv         LCDOUT  $FE,$A3
'pv         LCDOUT  $FE,$E3,"     "    'Limpia el espacio donde se coloca el voltaje positivo
'pv         LCDOUT  $FE,$E3

thanks for answering
I attach the code