ARM (LPCXXXX) Assembly Program for LED control by taking input from sensor

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@;      LED ON and OFF Program by taking input from sensor

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@;      Modified by GAURAV VERMA

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        AREA PROGRAM, CODE, READONLY

                                ENTRY

PINSEL0 EQU 0xE002C000

PINSEL1 EQU 0xE002C004

IOPIN   EQU 0xE0028000

IODIR   EQU 0xE0028008

IOSET   EQU 0xE0028004

IOCLR   EQU 0xE002800C

                               

                                ldr     r1,=PINSEL0             ; PINSEL0 controls pin 0-15

                                ldr     r2,=0x00000000      ;default GPIO function 00

                                str     r2, [r1]

                                ldr     r1,=IODIR

                                 ldr     r2,=0xFFFFFFFE  ; 0-INPUT 1-OUTPUT 0:31

                                str     r2, [r1]

BACK                     ldr     r0,=IOSET

                                ldr     r1,=0x7BFFFFFF ; SET ALL

                                str     r1, [r0]

                                ldr     r0,=IOPIN

key                          ldr     r3, [r0]

                                CMPS    r3, #0x03FFFFFF ; checking whether switch is pressed or not

                                beq     key

                               

                                ldr     r0,=IOCLR

                                ldr     r2,=0x00000010 ; CLR p0.4

                                str     r2, [r0]

                                BL WAIT

                                BAL BACK

WAIT                     MOV r4, #0x00100000

BACK1                   nop

                                SUBS r4, r4, #1

                                bne     BACK1

                                bx R14

                                           END