问 我用2812 的片子，编写了下面的一个小程序测试IO口：
void main()
{
  volatile unsigned int* GPAMUX = (volatile unsigned int*)0x70C0;
  volatile unsigned int* GPADIR = (volatile unsigned int*)0x70C1;
  volatile unsigned int* GPAQUAL= (volatile unsigned int*)0x70C3;
  volatile unsigned int* GPADAT = (volatile unsigned int*)0x70E0;
  volatile unsigned int* GPASET = (volatile unsigned int*)0x70E1;
  volatile unsigned int* GPACLEAR= (volatile unsigned int*)0x70E2;
  volatile unsigned int* GPATOGGLE= (volatile unsigned int*)0x70E3;
  int a;
  
  *GPAMUX =0x0000;
  *GPADIR =0xFFFF;
  *GPADAT =0x0505;
}
在调试时通过view-〉memory来观察以上几个寄存器的值，很可惜看不到有任何变化，万分不解，请高手指点 答 1: 看看GEL，是不是使能相关地址的读写 答 2: 谢谢问题解决了是ALLOW位的问题，只要对allow位置位 ，我不清楚受allow位影响的寄存器有哪些，我在手册上 没找到 ，能不能告知一二