Prj08--8088单板机C语言8255读取按键码

1.验证结果

2.代码片

     key_code=inp(PORT_8255_C)&0x0f;tiny_sprintf(buffer,"Key_code= 0X%x     \r\n",key_code);uart_str_send(buffer);

3.完整代码

#include "tiny_stdarg.h"  // 使用自定义可变参数实现#define ADR_273 0x0200
#define ADR_244 0x0400
#define  LED_PORT   0x800
#define  PC16550_THR   0x1f0
#define  PC16550_LSR   0x1f5
/
//基本的IO操作函数
/
char str[]="Hello World!  20250531  Very Ok!!!\r\n";
//char  buff[60]
char cx='A';
unsigned int cs_adr=0,ds_adr=0,ss_adr=0;/// @brief 
/// @param addr 
/// @param data 
void outp(unsigned int addr, char data)
// 输出一字节到I/O端口{ __asm{ mov dx, addrmov al, dataout dx, al}}
char inp(unsigned int addr)
// 从I/O端口输入一字节{ char result;__asm{ mov dx, addrin al, dxmov result, al}return result;}void register_read(void){__asm{mov ax,CSmov cs_adr,axmov ax,DSmov ds_adr,axmov ax,SSmov ss_adr,ax}}//串口发送函数void  uart_send(char x)
{int temp;while(1){temp=inp(PC16550_LSR);if((temp&0x20)==0x20){break;}}outp(PC16550_THR,x);}void uart_str_send(char *p)
{//int i=0;//char str1[20]="Hello World!\r\n";//char *p;//p=str1;while(*p!='\0'){uart_send(*p);p++;}/*for(i=0;i<14;i++){uart_send(str1[i]);}
*/}
///
/* sprintf()函数实现 */
/* tiny_sprintf.c */
#include "tiny_stdarg.h"static void itoa(unsigned num, int base, char *out) {char buf[6]; // 16位整数最大5位数字 + 结束符char *p = buf;int i = 0;if (num == 0) {*out++ = '0';*out = '\0';return;}while (num > 0) {int r = num % base;*p++ = (r < 10) ? (r + '0') : (r - 10 + 'a');num /= base;i++;}while (i-- > 0) {*out++ = *--p;}*out = '\0';
}int tiny_sprintf(char *buf, const char *fmt, ...) {va_list args;char *p = buf;const char *s = fmt;va_start(args, fmt);while (*s) {if (*s != '%') {*p++ = *s++;continue;}s++;switch (*s) {case 'd': {int num = va_arg(args, int);if (num < 0) {*p++ = '-';num = -num;}itoa(num, 10, p);while (*p) p++;s++;break;}case 'x': {unsigned num = va_arg(args, unsigned);itoa(num, 16, p);while (*p) p++;s++;break;}case 's': {char *str = va_arg(args, char *);while (*str) *p++ = *str++;s++;break;}case 'c': {char c = (char)va_arg(args, int);*p++ = c;s++;break;}case '%': {*p++ = '%';s++;break;}default: {*p++ = '%';*p++ = *s++;break;}}}*p = '\0';va_end(args);return p - buf;
}
///
//NMI 中断
//
/* NMI 计数器 */
volatile unsigned char nmi_count =10;
//设置中断失量表 
void set_int(unsigned char int_no, void * service_proc){ _asm{ push esxor ax, axmov es, axmov al, int_noxor ah, ahshl ax, 1shl ax, 1mov si, axmov ax, service_procmov es:[si], axinc siinc simov bx, csmov es:[si], bxpop es}}
//中断处理函数
/*
void _interrupt  near nmi_handler(void){nmi_count++;}*/
//
//8255  
//
// 定义8255端口地址 (根据原理图译码确定)
#define PORT_8255_A 0x200  // PA端口地址
#define PORT_8255_B 0x201  // PB端口地址
#define PORT_8255_C 0x202  // PC端口地址
#define PORT_8255_CTRL 0x203 // 控制寄存器地址// 数码管段码表 (共阴极)
unsigned char seg_codes[] = {0x3F, // 00x06, // 10x5B, // 20x4F, // 30x66, // 40x6D, // 50x7D, // 60x07, // 70x7F, // 80x6F  // 9
};// 延时函数
void delay(unsigned int ms) {for (unsigned int i = 0; i < ms; i++) {for (unsigned int j = 0; j < 100; j++) {// 空循环延时}}
}// 初始化8255
void init_8255() {// 控制字: 10000001 (0x81)// A口输出, B口输出, C口输出outp(PORT_8255_CTRL, 0x81);
}// 显示8位数字
void display_numbers() {unsigned char digits[] = {1, 2, 3, 4, 5, 6, 7, 8}; // 要显示的数字while (1) {  // 按任意键退出for (int i = 0; i < 8; i++) {// 设置位选 (选中当前位)outp(PORT_8255_B, ~(1 << i));// 设置段码outp(PORT_8255_A, ~seg_codes[digits[i]]);// 延时保持显示delay(1);// 关闭当前位显示 (消除鬼影)outp(PORT_8255_A, 0x00);}}
}////char  end_flag[5]={0x55,0x55,0x55,0x55,0x55};
extern void nmi_handler(void);
void main(void)
/*检测按键状态并由LED发光二极管显示,若按键闭合对应LED发光二极管点亮，若按键断开对应LED发光二极管灭.*/{ int i=0;char buffer[80];unsigned char key_code=0xff;   // 使用安全格式化//tiny_sprintf(buffer, "Hex: %x\n",255);// 使用安全格式化tiny_sprintf(buffer, "Decimal: %d    \n""Hex: %x    \n""String: %s    \r\n", -123, 0xABCD, "Hello");register_read();        //set_nmi_handler(); set_int(0x02, (void *)&nmi_handler);init_8255();while (1){//char button_state;//button_state=inp(ADR_244);//int i=0;//uart_str_send(str);uart_str_send(buffer);tiny_sprintf(buffer,"******************************************\r\n");uart_str_send(buffer);tiny_sprintf(buffer,"CS_ADR= 0X%x     \r\n",cs_adr);uart_str_send(buffer);tiny_sprintf(buffer,"DS_ADR= 0X%x     \r\n",ds_adr);uart_str_send(buffer);tiny_sprintf(buffer,"SS_ADR= 0X%x     \r\n",ss_adr);uart_str_send(buffer);tiny_sprintf(buffer,"NMI Interrupt count=%x    \r\n",nmi_count);uart_str_send(buffer);tiny_sprintf(buffer,"******************************************\r\n");uart_str_send(buffer);key_code=inp(PORT_8255_C)&0x0f;tiny_sprintf(buffer,"Key_code= 0X%x     \r\n",key_code);uart_str_send(buffer);//uart_send(cx);for(i=0;i<5000;i++);for(i=0;i<5000;i++);outp(LED_PORT, 0xff);for(i=0;i<5000;i++);for(i=0;i<5000;i++);outp(LED_PORT, 0x00);//display_numbers();}}
char  end_flag[5]={0x55,0x55,0x55,0x55,0x55};

4.项目进度