设计一个基于S3C2410的简单应用系统,绘制基本的连线原理图,用C语言编写相应的程序带有一个4x4键盘,各个按键对应编号为:0、1、2、3、4、5、6、7、8、9、A、B、C、D、E、F,某个键摁下时通过RS232口将对应的ASCII码发送出去。
时间: 2023-10-04 20:10:02 浏览: 70
好的,我会为你说明如何设计一个基于S3C2410的简单应用系统,包括绘制基本的连线原理图和用C语言编写相应的程序,带有一个4x4键盘,可以将按键对应的ASCII码发送出去。
首先,让我们来看一下S3C2410的基本连线原理图:
![S3C2410基本连线原理图](https://img-blog.csdn.net/20160420154934491)
在这个原理图中,S3C2410与外围电路相连。其中,4x4键盘连接到GPIO引脚,RS232口连接到UART引脚。
接下来,我们可以按照以下步骤来编写程序:
1. 设置GPIO引脚为输入模式,以便读取按键状态。
2. 初始化UART,并设置波特率为9600。
3. 在主循环中,读取键盘状态,根据按键状态发送对应的ASCII码。
下面是一个简单的C语言程序示例:
```c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <termios.h>
#define GPFCON 0x56000050
#define GPFDAT 0x56000054
#define ULCON0 0x50000000
#define UCON0 0x50000004
#define UFCON0 0x50000008
#define UMCON0 0x5000000C
#define UTRSTAT0 0x50000010
#define UTXH0 0x50000020
#define URXH0 0x50000024
#define UBRDIV0 0x50000028
#define UDIVSLOT0 0x5000002C
#define KEY_BUF_SIZE 16
void init_uart(void) {
int fd;
volatile unsigned long *ulcon;
volatile unsigned long *ucon;
volatile unsigned long *ufcon;
volatile unsigned long *umcon;
volatile unsigned long *ubrdiv;
volatile unsigned long *udivslot;
if ((fd = open("/dev/mem", O_RDWR | O_SYNC)) < 0) {
perror("open");
exit(1);
}
ulcon = mmap(NULL, 16, PROT_READ | PROT_WRITE, MAP_SHARED, fd, ULCON0);
ucon = mmap(NULL, 16, PROT_READ | PROT_WRITE, MAP_SHARED, fd, UCON0);
ufcon = mmap(NULL, 16, PROT_READ | PROT_WRITE, MAP_SHARED, fd, UFCON0);
umcon = mmap(NULL, 16, PROT_READ | PROT_WRITE, MAP_SHARED, fd, UMCON0);
ubrdiv = mmap(NULL, 16, PROT_READ | PROT_WRITE, MAP_SHARED, fd, UBRDIV0);
udivslot = mmap(NULL, 16, PROT_READ | PROT_WRITE, MAP_SHARED, fd, UDIVSLOT0);
*ulcon = 0x3;
*ucon = 0x5;
*ufcon = 0x0;
*umcon = 0x0;
*ubrdiv = 26;
*udivslot = 0x80000000 | (0x1 << 16);
munmap((void *)ulcon, 16);
munmap((void *)ucon, 16);
munmap((void *)ufcon, 16);
munmap((void *)umcon, 16);
munmap((void *)ubrdiv, 16);
munmap((void *)udivslot, 16);
close(fd);
}
void send_char(char c) {
volatile unsigned long *utrstat;
volatile unsigned long *utxh;
utrstat = (volatile unsigned long *)UTRSTAT0;
utxh = (volatile unsigned long *)UTXH0;
while (!(*utrstat & (0x1 << 1)));
*utxh = c;
}
void send_string(char *s) {
while (*s != '\0') {
send_char(*s);
s++;
}
}
char read_key(void) {
int fd;
volatile unsigned long *gpfcon;
volatile unsigned long *gpfdat;
if ((fd = open("/dev/mem", O_RDWR | O_SYNC)) < 0) {
perror("open");
exit(1);
}
gpfcon = mmap(NULL, 16, PROT_READ | PROT_WRITE, MAP_SHARED, fd, GPFCON);
gpfdat = mmap(NULL, 16, PROT_READ | PROT_WRITE, MAP_SHARED, fd, GPFDAT);
*gpfcon &= ~(0xff << 8);
*gpfcon |= 0x55 << 8;
unsigned char key_buf[KEY_BUF_SIZE];
int key_buf_ptr = 0;
while (1) {
unsigned char key = 0;
unsigned long dat = *gpfdat & 0xff00;
if (dat != 0xff00) {
switch (dat) {
case 0xfe00:
key = 0;
break;
case 0xfd00:
key = 1;
break;
case 0xfb00:
key = 2;
break;
case 0xf700:
key = 3;
break;
case 0xef00:
key = 4;
break;
case 0xdf00:
key = 5;
break;
case 0xbf00:
key = 6;
break;
case 0x7f00:
key = 7;
break;
default:
break;
}
if (key != 0) {
key_buf[key_buf_ptr++] = key;
if (key_buf_ptr >= KEY_BUF_SIZE) {
key_buf_ptr = 0;
}
}
}
usleep(10000);
}
munmap((void *)gpfcon, 16);
munmap((void *)gpfdat, 16);
close(fd);
}
int main(void) {
init_uart();
while (1) {
char c = read_key() + '0';
send_char(c);
}
return 0;
}
```
在这个程序中,我们使用了mmap函数来映射物理内存地址,以便通过指针访问S3C2410的GPIO和UART寄存器。我们设置GPIO引脚为输入模式,并在主循环中读取键盘状态,根据按键状态发送对应的ASCII码。
希望这个示例程序对你有所帮助!