program7.c

来自「嵌入式系统基础课件」· C语言 代码 · 共 63 行

#include <dos.h>
#include "libepc.h"
#include "serial.h"

/* Function prototypes */
void InitOutBound(void) ;
void InitInBound(void) ;
void InitSerial(void) ;

void OutBound(void) ;
void InBound(void) ;

QUEUE *inbound_queue ;

int main()
	{
	inbound_queue = QueueCreate(sizeof(char), 20) ;

	ClearScreen(0x07) ;
	SetCursorVisible(TRUE) ;
	InitSerial() ;

	InitOutBound() ;
	InitInBound() ;

	for (;;)
		{
		OutBound() ;
		InBound() ;
		}

	return 0 ;
	}

void InitSerial(void)
	{
	/* Disable interrupts during initialization */
	disable() ;

	/* 9600 baud */
	outportb(SER_LCR, SER_LCR_DLAB) ;
	outportb(SER_DLO, 12) ;
	outportb(SER_DHI, 0) ;

	/* 8 data bits, even parity, 1 stop bit */
	outportb(SER_LCR, 0x1B) ;

	/* Enable only receiver data ready interrupts */
	outportb(SER_IER, 0x01) ;

	/* Request to send, data terminal ready, enable interrupts */
	outportb(SER_MCR, SER_MCR_RTS|SER_MCR_DTR|SER_MCR_OUT2) ;

	/* Store address of ISR in IDT */
	SetISR(IRQ2INT(SER_IRQ), SerialISR) ;

	/* Unmask the UART's IRQ line */
	outportb(0x21, inportb(0x21) & ~SER_MSK) ;

	/* Re-enable interrupts */
	enable() ;
	}