综述

STC12C5A60S2拥有双串口，波特率由Timer1或者独立波特率发生器(BRT)产生。

对于串口1，我们可以使用TImer1或者BRT产生波特率。
对于串口2，我们只能使用BRT产生波特率。

UART所涉及的寄存器

UART1涉及寄存器

UART2涉及寄存器

SCON

S2CON

AUXR

例子

UART1_Timer1

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#include <reg52.h>

sfr AUXR = 0x8e;

#define TIMS  0xdc		// (1/11059200)*9600*32*n = 1   n = 36	 TIMS = 256-36

/************
11.0592MHZ Timer1  1t  no double BAUD   9600
*************/

unsigned char num;

void UART_Init()
{
	EA = 1;
	ES = 1;
	
	TR1 = 1;			//enable Timer1
	
	TMOD = 0x20;		// 8bit reload
	
	AUXR = 0x40;		//	UART1*12
	
	TH1 = TL1 = TIMS;
	
	SCON = 0x50;		// Mode 1  enable RXD	
	PCON = 0x00;		// BAUD no double 
	
}

void main()
{
	UART_Init();
	while(1);
}

void UART1() interrupt 4 
{
	if(RI)
	{
		RI = 0;
		num = SBUF;
		SBUF = num;
		while(!TI);		// wait TXD finish
	}
	
}

UART2_BRT

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#include <reg52.h>

sfr AUXR = 0x8e;

sfr S2CON = 0x9A;
sfr S2BUF = 0x9B;
sfr BRT = 0x9c;


sfr IE2 = 0xAF;
sfr AUXR1 = 0xA2;

sbit LED = P3^0;

#define S2RI  0x01
#define S2TI  0x02

unsigned char dat;

#define TIMS (11059200L*2/32/115200)

void UART2_BRT_Init()
{
	EA = 1;
	IE2 =0x01;
	
	AUXR = 0x1C;		// 1t double BAUD
	
	BRT = 256 - TIMS;
	
	S2CON = 0x50;		// 8 bit  enable RXD
	
}



void main()
{
	UART2_BRT_Init();
	
	while(1)
	{
		
		if(dat==0x01)
		{	
			LED = 1;
		}
		if(dat==0x00)
		{
			LED = 0;
		}
			
	}
	
}

void UART2_BRT() interrupt 8  using 1
{
	if(S2CON&S2RI)				// can not  addressable
	{
		S2CON &= ~S2RI;
		dat = S2BUF ;
		S2BUF = dat;
	}
	
	if(S2CON&S2TI)
	{
		S2CON &= ~S2TI;
	}
		
	
}