S3C2410实习代码--Flash LED

时间：2009-06-22 来源：creatory

;Function:Flash LED.asm
;Date:2009/06/22
;Author:creatory GPFCON EQU 0x56000050
GPFDAT EQU 0x56000054
GPFUP EQU 0x56000058 EXPORT FLASHLED
AREA Init,CODE,READONLY
FLASHLED
;SET GPF4-GPF7 output
LDR R0,=GPFCON
LDR R1,[R0]
BIC R1,R1,#0xFF00
ORR R1,R1,#0x5500
STR R1,[R0]

;disable the up
LDR R0,=GPFUP
LDR R1,[R0]
ORR R1,R1,#0xF0
STR R1,[R0]

LOOP
LDR R2,=GPFDAT
LDR R3,[R2]
;clear the [7:4] bits
BIC R3,R3,#0xF0

;let GPF6 output 0
;1011,0000 ORR R3,R3,#0xB0
STR R3,[R2]
;call delay
LDR R0,=0x2FFFF
BL DELAY

LDR R3,[R2]
BIC R3,R3,#0xF0
;let GPF7 output 0
;0111,0000 ORR R3,R3,#0x70
STR R3,[R2]
;call delay
LDR R0,=0x2FFFF
BL DELAY

LDR R3,[R2]
BIC R3,R3,#0xF0
;let GPF5 output 0
;1101,0000

ORR R3,R3,#0xD0
STR R3,[R2]
;call delay
LDR R0,=0x2FFFF
BL DELAY

LDR R3,[R2]
BIC R3,R3,#0xF0
;let GPF4 output 0
;1110,0000 ORR R3,R3,#0xE0
STR R3,[R2]
;call delay
LDR R0,=0x2FFFF
BL DELAY

B LOOP ;jump back

DELAY
SUB R0,R0,#0x1
CMP R0,#0x0
BNE DELAY
MOV PC,LR

END

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