serial.c

来自「用keil仿真arm芯片的一个简单程序」· C语言 代码 · 共 30 行

/*------------------------------------------------------------------------------
SERIAL.C:  Low Level Serial Routines

Copyright 1995-2002 Keil Software, Inc.
------------------------------------------------------------------------------*/

#include <91M40800.H>                      /* AT91M40800 definitions          */

#define CR     0x0D


int putchar (int ch)  {                    /* Write character to Serial Port  */

  if (ch == '\n')  {
    while (!(US0_CSR & US_TXRDY));
    US0_THR = CR;                          /* output CR */
  }
  while (!(US0_CSR & US_TXRDY));
  return (US0_THR = ch);
}


int getchar (void)  {                      /* Read character from Serial Port */

  while (!(US0_CSR & US_RXRDY));

  return (US0_RHR);
}