头文件.h

8250扩展串口的单片机C51例程和相关资料。

unsigned char RR_iHead;     /* receiver head index */    //头指针
unsigned char RR_iTail;     /* receiver tail index */    //尾指针
unsigned char RR_cLev;      /* receiver buffer count */
unsigned char RR_cMax;      /* receiver buffer count */

unsigned char TR_iHead;     /* transmitter head index */
unsigned char TR_iTail;     /* transmitter tail index */
unsigned char TR_cLev;      /* transmitter buffer count */
unsigned char TR_cMax;      /* transmitter buffer count */

unsigned char UnGotCh;      /* saved char for ungetch() */  //接收的字符

unsigned char SerFlags;     /* serial flag */               //串口标志

bit FlagTransIdle;       //当发送完成后置1
bit FlagStripOutLF;     /* don't send linefeeds */
bit FlagCvtInCR;        /* convert incoming CR to LF */

unsigned char TestBits;

#define INRINGSIZE 128      /* must be <= 254 to avoid wraps */
#define OUTRINGSIZE 250     /* ditto */

#define T1RELOAD 253

#define CR 13
#define LF 10
#define ESC 27

#define EOF -1

unsigned char xdata RRing[INRINGSIZE];     //接收缓冲区
unsigned char xdata TRing[OUTRINGSIZE];    //发送缓冲区

int     putstr (const char *);
int     putch(int);
int     chkch();
int     getch();
void    SerWaitOutDone();
int     SerFlushIn();
int     putc(int TransChar);