18f1320 I/O ports

[saravana_3]

after the helps from the form members, I am able to run ,and set my I/O ports in the 18f1320, I can control all the outputs, but my input cannot be read

BTFSS PORTA,0

GOTO START

BSF PORTB,0



as per the above code when I press the portA,0 switch I should get the output at the portB,0 but I am not getting.



BTFSC PORTA,0

GOTO START

BSF PORTB,0



as per the above code once download the program I am getting the output at the portB,0 becaus the portA,0 switch is not pressed, but once I press the portA,0 switch, there should not be any output at the portB,0 but still the output is there.

i cannot find out the problem, my codes are bellow please help me,



list p=18F1320

include <p18F1320.inc> ;IF we use this not need to declare port address

radix hex





;----------------------------------------------------------------------

; cpu equates (memory map)

Status equ 0xFD8

PORTA equ 0xF80 ; define the potA address

PORTB equ 0xF81 ;

TRISA equ 0xF92

TRISB equ 0xF93

ADCON0 EQU 0XFC2

ADCON1 EQU 0XFC1

LATA EQU 0XF89

LATB EQU 0XF8A

;----------------------------------------------------------------------

org 0x000





CLRF PORTA ;clearing the output

MOVLW 0X00

MOVWF ADCON0

MOVLW 0X7F ;configure the A/D

MOVWF ADCON1 ;for digital inputs

MOVLW 0xFF

MOVWF TRISA,0

;MOVLW 0xD0 ;values used to set the port

;MOVWF TRISA

;MOVWF LATA ;'11111111'

CLRF PORTB ;clearing the output

MOVLW 0X70 ;

MOVWF ADCON1 ;digital I/O pins

MOVLW 0x00

MOVWF TRISB,0

;MOVLW 0XCF ;values used to set the port

;MOVWF TRISB

;MOVWF LATB ;'00000000'









Start









BTFSS PORTA,0

;BTFSC PORTA,0

GOTO Start

BSF PORTB,0



goto Start

END

[Benj]

Hello Saran

You are in Bank0 of memory.

To modify the TRIS registers you have to be in bank 1 of memory.

To change from bank 0 to bank 1 you have to set the RP0 bit in the status register, Refer to the device datasheet on how to do this.

Once you have modified the TRIS registers you can move back into Bank0 to control the I/O.