2440_WinCE操作GPIO

计算机基本知识windows ce系统将gpio的实地址(例如2440的g pio的基地址为0x56000000)映射到虚拟地址空间（gpio对应为0xb1600000），这样，通过对这段虚拟地址空间的操作，就能够完成对gpio或者其他片内资源的控制、输入输出工作。

要操作一个平台的gpio，在其对应bsp中按照基地址，找到虚拟地址，并且找到方便操作这个地址的数据结构就可以了，要害函数就是 virtualalloc和virtualcopy。

下面以操作samsung s3c2440的gpio为例，讲述这个步骤：
1.首先在bsp中的s2440.h文件，找到虚拟地址映射以及操作gpio的寄存器结构体(这个在自己制作一些非凡设备的bsp时，会依据需要而发生更改)
#define iop_base 0xb1600000 // 0x56000000
typedef struct {
unsigned int rgpacon; // 00
unsigned int rgpadat;
unsigned int rpad1[2];
unsigned int rgpbcon; // 10
unsigned int rgpbdat;
unsigned int rgpbup;
unsigned int rpad2;
unsigned int rgpccon; // 20
unsigned int rgpcdat;
unsigned int rgpcup;
unsigned int rpad3;
unsigned int rgpdcon; // 30
unsigned int rgpddat;
unsigned int rgpdup;
unsigned int rpad4;
unsigned int rgpecon; // 40
unsigned int rgpedat;
unsigned int rgpeup;
unsigned int rpad5;
unsigned int rgpfcon; // 50
unsigned int rgpfdat;
unsigned int rgpfup;
unsigned int rpad6;
unsigned int rgpgcon; // 60
unsigned int rgpgdat;
unsigned int rgpgup;
unsigned int rpad7;
unsigned int rgphcon; // 70
unsigned int rgphdat;
unsigned int rgphup;
unsigned int rpad8;
unsigned int rmisccr; // 80
unsigned int rdckcon;
unsigned int rextint0;
unsigned int rextint1;
unsigned int rextint2; // 90
unsigned int reintflt0;
unsigned int reintflt1;
unsigned int reintflt2;
unsigned int reintflt3; // a0
unsigned int reintmask;
unsigned int reintpend;
unsigned int rgstatus0; // ac
unsigned int rgstatus1; // b0
unsigned int rgstatus2; // b4 ;;; shl
unsigned int rgstatus3; // b8
unsigned int rgstatus4; // bc
unsigned int rfltout; // c0
unsigned int rdsc0;
unsigned int rdsc1;
unsigned int rmslcon;
unsigned int rgpjcon; // d0
unsigned int rgpjdat;
unsigned int rgpjup;
unsigned int rpad9;
}iopreg;
二、因为我用的mini2440开发板的gpb0接在蜂鸣器上，所以我以操作gpb0为例编写代码。

这样给gpb0一个高电平，那么蜂鸣器就会响，反之蜂鸣器就会停止发声
#ifdef __cplusplus
extern "c"
{
#endif
bool virtualcopy( pvoid, pvoid, dword, dword );
#ifdef __cplusplus
}
#endif
void gpio() //通过gpio控制蜂鸣器
{
volatile iopreg *v_pioregs;
v_pioregs = (volatile iopreg *)virtualalloc(0, sizeof(iopreg), mem_reserve, page_noaccess);
if(v_pioregs)
{
if(virtualcopy((pvoid)v_pioregs, (pvoid)iop_base, sizeof(iopreg), page_readwrite | page_nocache))
{
v_pioregs->rgpbcon = 1; //
将gpb0设置为output
v_pioregs->rgpbdat = 0x3ff; //设置为高电平，蜂鸣器发声
sleep(3000);
v_pioregs->rgpbdat = 0; //恢复为低电平，蜂鸣器停止发声
}
virtualfree((lpvoid)v_pioregs, 0, mem_release);
v_pioregs = null;
}
}
@written by .cpp。