问 答 1: 贴一个#define uchar unsigned char
#define uint unsigned int
#define FOSC       11059200ul
#define BAUD       9600
#define SMODX      0
#define TH1_VAL    (256 - (uchar)(FOSC * (1<<SMODX) * 1.0 / 384 / BAUD))
#define TL1_VAL    TH1_VAL

sbit DIN  =P1^3;
sbit DOUT =P1^2;
sbit SCLK =P1^1;
sbit CS   =P1^0;

void Delayus(uchar t)
{
    for(; t>0; t--)
            ;
}

uchar Byte3100(uchar dat) reentrant
{
    uchar i;
    
    DOUT = 1;
    DIN = 1;
    for(i=0; i<8; i++)
    {
        if(dat & 0x80)
            DIN = 1;
        else
            DIN = 0;
        SCLK = 1;
        dat <<= 1;
        dat |= DOUT;
        SCLK = 0;
    }
    return dat;
}

uchar Send3100(uchar tx1,uchar tx2) reentrant
{
    CS = 0;
    Byte3100(tx1);
    tx1 = Byte3100(tx2);
    CS = 1;
    return tx1;
}

void Init3100(void)
{
    uchar dat,i=0;
    do
    {
        Send3100(0xc4,0x0a);         //0b:4800,0a:9600
        Delayus(200);
        dat = Send3100(0x40,0x00);
    }while((dat!= 0x01)&&(++i<5));
    Send3100(0x84,0x00);
    Delayus(200);
}

答 2: 可用模拟的,网上的一个短距离能跑到19200,11.0592M晶振 答 3: SC16IS752多好的东西！