原创 S3C2440GPIO 以YL-PS3C2440为例

S3C2440有GPA,GPB,GPC......GPJ一共9组,比2410多了一组<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

GPIO无非是用来进行输入输出的,那么肯定有寄存器进行控制

对于输入的话,我们一定可以通过读取寄存器来确定引脚的高电平还是低电平;

对于输出的话,我们一定也可以通过写某个寄存器来让这个引脚输出高低电平.

1控制类的:

GPxCON

portA有点与众不同啊,GPACON每一位对应着一根引脚(23根)

0:代表输出;1:相应的引脚为地址线或用于地址控制

对于PORT B-PORT J的话,GPxCON中每两位控制一根引脚

00:输入;01:输出;10:特殊功能;11:保留

2.数据

GPxDAT

用于读或者写

3.GPxUP

1:不使用内部的上拉电阻;0:使用内部上拉电阻

从手册中可以得知（原来很多东西都可以查手册的）：

GPACON 0x56000000 ← W R/W Port A Control
GPADAT 0x56000004 Port A Data
GPBCON 0x56000010 Port B Control
GPBDAT 0x56000014 Port B Data
GPBUP 0x56000018 Pull-up Control B
GPCCON 0x56000020 Port C Control
GPCDAT 0x56000024 Port C Data
GPCUP 0x56000028 Pull-up Control C
GPDCON 0x56000030 Port D Control
GPDDA1T 0x56000034 Port D Data
GPDUP 0x56000038 Pull-up Control D
GPECON 0x56000040 Port E Control
GPEDAT 0x56000044 Port E Data
GPEUP 0x56000048 Pull-up Control E
GPFCON 0x56000050 Port F Control
GPFDAT 0x56000054 Port F Data
GPFUP 0x56000058 Pull-up Control F
GPGCON 0x56000060 Port G Control
GPGDAT 0x56000064 Port G Data
GPGUP 0x56000068 Pull-up Control G
GPHCON 0x56000070 Port H Control
GPHDAT 0x56000074 Port H Data
GPHUP 0x56000078 Pull-up Control H
GPJCON 0x560000D0 Port J Control
GPJDAT 0x560000D4 Port J Data
GPJUP 0x560000D8 Pull-up Control J

GPIO操作实例：LED与按键

GPFCON Bit Description
GPF7 [15:14] 00 = Input 01 = Output
10 = EINT[7] 11 = Reserved
GPF6 [13:12] 00 = Input 01 = Output
10 = EINT[6] 11 = Reserved
GPF5 [11:10] 00 = Input 01 = Output
10 = EINT[5] 11 = Reserved
GPF4 [9:8] 00 = Input 01 = Output
10 = EINT[4] 11 = Reserved
GPF3 [7:6] 00 = Input 01 = Output
10 = EINT[3] 11 = Reserved
GPF2 [5:4] 00 = Input 01 = Output
10 = EINT2] 11 = Reserved
GPF1 [3:2] 00 = Input 01 = Output
10 = EINT[1] 11 = Reserved
GPF0 [1:0] 00 = Input 01 = Output
10 = EINT[0] 11 = Reserved

怎么想都觉得书上莫名其妙，查了一下确实有错。

@******************************************************************************

@ File：led_on.S

@ 功能：LED点灯程序，点亮LED1

@******************************************************************************      

.text

.global _start

_start:    

            LDR     R0,=0x56000050            @ R0设为GPFCON寄存器。此寄存器

                                               @ 用于选择端口F各引脚的功能：

                                               @ 是输出、是输入、还是其他

            MOV     R1,#0x00000100       

            STR     R1,[R0]                    @ 设置GPF4为输出口, 位[9:8]=0b01

            LDR     R0,=0x56000054            @ R0设为GPFDAT寄存器。此寄存器

                                               @ 用于读/写端口F各引脚的数据

            MOV     R1,#0x00000000           @ 此值改为0x00000010,

                                               @ 可让LED1熄灭

            STR     R1,[R0]                    @ GPF4输出0，LED1点亮

MAIN_LOOP:

            B       MAIN_LOOP