C语言实现在8051单片机片外扩62256芯片(32K Bytes RAM),将其映射到8051芯片的外部数据空间地址0x8000—0xFFFF并编程实现对62256芯片RAM自检,
时间: 2023-12-14 10:36:51 浏览: 33
下面是一个简单的C语言程序,可以实现在8051单片机片外扩62256芯片,并将其映射到8051芯片的外部数据空间地址0x8000—0xFFFF,并编程实现对62256芯片RAM自检。
```c
#include <reg52.h>
#define MEM_START_ADDR 0x8000
#define MEM_END_ADDR 0xFFFF
#define RAM_SIZE 0x8000 // 32K Bytes
sbit CS = P1^4; // 62256芯片片选引脚
void delay(unsigned int t)
{
while(t--);
}
void mem_write(unsigned int addr, unsigned char dat)
{
CS = 0; // 使能片选
P0 = dat;
((unsigned char*)&addr)[1] = ((unsigned char*)&addr)[1] & 0x1F;
P2 = ((unsigned char*)&addr)[1];
P2 = P2 | 0x80;
P2 = P2 & 0xBF;
P2 = ((unsigned char*)&addr)[0];
P2 = P2 | 0x80;
P2 = P2 & 0xBF;
delay(1);
CS = 1; // 禁用片选
}
unsigned char mem_read(unsigned int addr)
{
unsigned char dat;
CS = 0; // 使能片选
((unsigned char*)&addr)[1] = ((unsigned char*)&addr)[1] & 0x1F;
P2 = ((unsigned char*)&addr)[1];
P2 = P2 | 0x80;
P2 = P2 & 0xBF;
P2 = ((unsigned char*)&addr)[0];
P2 = P2 | 0x80;
P2 = P2 & 0xBF;
delay(1);
dat = P0;
CS = 1; // 禁用片选
return dat;
}
void mem_test(unsigned int addr)
{
unsigned char dat;
unsigned int i;
for (i = 0; i < RAM_SIZE; i++) {
mem_write(addr + i, (unsigned char)i);
}
for (i = 0; i < RAM_SIZE; i++) {
dat = mem_read(addr + i);
if (dat != (unsigned char)i) {
// 自检失败
while (1);
}
}
// 自检通过
}
void main()
{
mem_test(MEM_START_ADDR);
while (1);
}
```
在这个程序中,我们首先定义了62256芯片的片选引脚为P1^4,并且定义了mem_write和mem_read两个函数,用于写入和读取62256芯片上的数据。我们还定义了mem_test函数,用于进行62256芯片RAM的自检。
在main函数中,我们调用mem_test函数来进行自检,如果自检失败,则程序会停止运行。否则,程序将一直运行,等待进一步的操作。
注意:在实际应用中,需要根据具体的硬件连接情况来修改程序中的引脚定义和地址范围。