51单⽚机使⽤串⼝printf
#define BIT(x)                  ((unsigned int)((unsigned int)1<<x))
串⼝初始化
/*----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------*/
void Uart0_Init(unsigned int baud)
{
unsigned long tmp;
#if 0
P2CR  &= ~BIT(0);    //Input Mode
P2PCR |= BIT(0);    //Enable pull-up resistor
P2    |= BIT(0);
P2CR  |=  BIT(1);  //Output Mode
P2PCR &= ~(BIT(1)); //Disable pull-up resistor
P2    |=  BIT(1);
#endif
/* Config Uart0：Mode 1, 8-bits asynchronous. */
SCON = 0x50;
PCON |=0x80;            //Double baud rate
tmp = 16000000/16/baud; //16000000UL*2/2/16/baud;
tmp = 65536 - tmp;
RCLK = 0;              //T4 create rxd baud rate
TCLK = 0;              //T4 create txd baud rate
_push_(INSCON);
Select_Bank1();
T4CLKS = 0;            //T4 Clock select = Sysclk = 16MHz;
T4PS1 = 0;              //T4 Prescaler = 1/1;
T4PS0 = 0;
T4M1 = 0;              //T4 mode select bits = 01, T4 as Baud rate generator.
T4M0 = 1;
TL4 = (unsigned char)tmp;
TH4 = (unsigned char)(tmp>>8);模拟串口使用printf函数
TR4 = 1;
Select_Bank0();
_pop_(INSCON);
REN = 1;                //Enable Receive
//ES0 = 1;              //Enable Uart0 Interrupt
//TI = 1;              //printf need
}
printf重映射
/*----------------------------------------------------------------------------*/
//printf call
/*----------------------------------------------------------------------------*/
char putchar(char ch)
{
//ES=0;  //Disable Uart0 Interrupt
TI = 0;
SBUF = (unsigned char)ch;
while (!TI);
TI = 0;
//ES=1;  //Enable Uart0 Interrupt
return (ch);
}