uart0_init.c

来自「基于8051F单片机,实现1024点的FFT 用C 语言实现的.效果与FPGA」· C语言 代码 · 共 50 行

#include "common.h"



//-----------------------------------------------------------------------------
// UART0_Init
//-----------------------------------------------------------------------------
//
// Configure the UART0 using Timer1, for <baudrate> and 8-N-1. In order to
// increase the clocking flexibility of Timer0, Timer1 is configured to count
// SYSCLKs.
//
// To use this routine SYSCLK/BAUDRATE/16 must be less than 256. For example,
// if SYSCLK = 50 MHz, the lowest standard baud rate supported by this
// routine is 19,200 bps.

void UART0_Init (void)
{
char old_SFRPAGE = SFRPAGE;         // Store current SFRPAGE

   SFRPAGE = UART0_PAGE;            // Switch to UART0 Page

   SCON0  = 0x50;                   // SCON0: mode 0, 8-bit UART, enable RX
   SSTA0  = 0x10;                   // Timer 1 generates UART0 baud rate and
                                    // UART0 baud rate divide by two disabled
   SFRPAGE = TIMER01_PAGE;
   TMOD   &= ~0xF0;
   TMOD   |=  0x20;                 // TMOD: timer 1, mode 2, 8-bit reload

   TH1 = -(SYSCLK/BAUDRATE/16);     // Set the Timer1 reload value
                                    // When using a low baud rate, this
                                    // equation should be checked to ensure
                                    // that the reload value will fit in
                                    // 8-bits.

   CKCON |= 0x10;                   // T1M = 1; SCA1:0 = xx


   TL1 = TH1;                       // initialize Timer1
   TR1 = 1;                         // start Timer1

   SFRPAGE = UART0_PAGE;
   TI0 = 1;                         // Indicate TX0 ready

   SFRPAGE = old_SFRPAGE;           // restore SFRPAGE

}