Capacitive sensing module on 16f1936

[grahamg]

I am not sure weather I am doing something incorrectly or maybe there is a problem with the data sheet.

DEFINE OSC 4

@  __CONFIG    _CONFIG1, _LVP_OFF & _FCMEN_ON & _IESO_ON & _BOREN_ON & _CPD_OFF & _CP_OFF & _MCLRE_ON & _PWRTE_ON & _WDTE_OFF & _FOSC_XT
@  __CONFIG    _CONFIG2, _WRT_HALF & _BORV_25 & _PLLEN_OFF

db0             VAR  PORTC.0          'o 0:3 digit data
db1             VAR  PORTC.1          'o
db2             VAR  PORTC.2          'o PIN13
db3             VAR  PORTC.3          'o PIN14
digitsel1       VAR  PORTC.4          'o PIN15
digitsel2       VAR  PORTC.5          'o PIN16
TX              VAR  PORTC.6          'o
RX              VAR  PORTC.7          'i

cs             VAR  PORTA.0           'o
nu1            VAR  PORTA.1           'o
nu2            VAR  PORTA.2           'o
                                                  'EXPECTED    ACTUAL
BUT1           VAR  PORTB.0          'i   pin21    03A-O3B     03C-03D      
UP             VAR  PORTB.1          'i   pin22    03C-03D     03E-03F
BUT3           VAR  PORTB.2          'i   pin23    03E-03F     040-041
ENTER          VAR  PORTB.3          'i   pin24    040-041     042-043
DOWN           VAR  PORTB.4          'i   pin25    042-043     044-045
BUT2           VAR  PORTB.5          'i   pin26    044-045     03A-03B
nu3            VAR  PORTB.6          'o   pin27
nu4            VAR  PORTB.7          'o   pin28

INDEX            var  byte
BASEVAL       VAR  byte[12]         'AFTER COMPILING BASEVAL=ADDRESS 03A


GOTO  START:
DEFINE INTHAND MYINT
ASM      
MYINT             CLRF    BSR                        ;SET PAGE=0
                  BTFSS   PIR1,TMR1GIF               ;TEST FOR TIMER1 GATE INTERRUPT 
                  BRA     TIMER0                     ;MUST BE TIMER0
                  BCF     T1CON,TMR1ON               ;STOP TIMER1
                  CLRF    FSR0H                      ;CLEAR FSR HIGH BYTE
                  MOVLW   _BASEVAL                   ;MOV BASEVAL TO FSR0 LOW
                  MOVWF   FSR0L
                  MOVLW   6                          ;MOVE 6 TO WREG
                  SUBWF   _INDEX,W                   ;SUBTRACT W FROM INDEX
                  BTFSC   STATUS,Z                   ;TEST FOR ZERO
                  CLRF    _INDEX                     ;IF ZERO THEN ZERO INDEX  
                  MOVF    _INDEX,w                   ;MOVE INDEX TO W 
                  MOVWF   CPSCON1                    ;MOV W TO CAPACITIVE SENSING CHANNEL
                  LSLF    WREG,W                     ;MULTIPY W BY 2
                  ADDWF   FSR0L,F                    ;ADD W  TO BASEVAL
                  MOVF    TMR1L,W                    ;MOVE TIMER1 LOW TO WREG
                  MOVWI   INDF0++                    ;SAVE WREG TO BASEVAL+INDEX*2 AND INC FSR0 
                  MOVF    TMR1H,w                    ;MOVE TIMER1 HIGH BYTE TO WREG
                  MOVWI   INDF0++                    ;SAVE WREG TO BASEVAL+INDEX*2+1
                  INCF    _INDEX,f                   ;INCREMENT INDEX
                  CLRF    TMR1L                      ;CLEAR TIMER1 LOW
                  CLRF    TMR1H                      ;CLEAR TIMER1 HIGH
                  BSF     T1CON,TMR1ON               ;TURN TIMER 1 ON
                  BCF     PIR1,TMR1GIF               ;CLEAR TIMER 1 GATE INTERRUPT FLAG
                  RETFIE                             ;RETURN FROM INTERRUPT
TIMER0            BCF     INTCON,TMR0IF              ;CLEAR TIMER0 INTERRUPT FLAG 
                  RETFIE                             ;RETURN FROM INTERRUPT
ENDASM


START:
ANSELA=$00
TRISA=$00
ANSELB=$3F
TRISB=$3F
PORTA=$01
PORTB=$00
PORTC=$30
TRISC=$80
CPSCON0=$8C                 'BITS 2,3=OSCILLATOR RANGE
CPSCON1=$00                 'BITS 0-2 SELECT CHANNEL
OPTION_REG=$C4
T1CON=$C5
T1GCON=$E1
PIR1=$00
PIE1=$80
INDEX=0
INTCON=$E0
loop1:
goto loop1

When I compile the above code and run it with the ICD3 I appear to get valid timer1 values in sfr locations 03a-045. When I touch the touch pad connected to pin 26 (CPS5) the value in 03a,03b changes. All other locations appear to be offset by a vale of 2. See expected,actual addresses after the port definitions. Can anyone explain why this is like it is?

Graham Guthrie