usart.c

最新版IAR FOR ARM（EWARM）5.11中的代码例子

/*************************************************************************
 *
 *    Used with ICCARM and AARM.
 *
 *    (c) Copyright IAR Systems 2007
 *
 *    File name   : usart.c
 *    Description : Main file
 *
 *    History :
 *    1. Date        : August 2, 2007
 *       Author      : Stanimir Bonev
 *       Description : Create
 *
 *  This example project shows how to use the IAR Embedded Workbench for ARM
 * to develop code for the Samsung-S3F4A0K evaluation board. It shows
 * basic use of USAR0 in asynchronous mode.
 *  The example return asterisk and echo of the received character
 *  UART setting : 115200, 8 bit, no parity, 1 stop bit
 *
 * Jumpers:
 *  J43 5-6 - filled
 *  J42 5-6 - filled
 *  All other jumpers are in default position regarding board's manual
 *
 *    $Revision: 18083 $
 **************************************************************************/
#include <samsung\ios3f4a0k.h>
#include "arm_comm.h"
#include "board.h"

/*************************************************************************
 * Function Name: main
 * Parameters: none
 * Return: none
 *
 * Description: Main
 *
 *************************************************************************/
void main (void)
{
  // Enable PIO0 blocks for USART0 I/O configuration
  PIO0_ECR = 1;
  // Disable PIO function for USART0 signals - RXD and TXD  (P0.19, P0.20)
  PIO0_PDR = (1UL<<19) | (1UL << 20);
  // Disable PIO0 blocks
  PIO0_DCR = 1;
  // Set USART0 RX and TX functions
  IOCONF_MR2_bit.PIO0_19_F3EN = 1;
  IOCONF_MR2_bit.PIO0_20_F3EN = 1;
  // Enable USART0 blocks
  US0_ECR = 1 << 1;
  // USART Software Reset
  US0_CR = 1;
  // Configure USART Mode
  US0_MR_bit.LIN      = 0;  // Disable LIN protocol on USART
  US0_MR_bit.CLKS     = 0;  // CLKS Clock = PCLK
  US0_MR_bit.CHRL     = 3;  // 8 bits
  US0_MR_bit.SYNC     = 0;  // USART operates in Asynchronous Mode
  US0_MR_bit.PAR      = 4;  // No parity
  US0_MR_bit.NBSTOP   = 0;  // 1 stop bit
  US0_MR_bit.CHMODE   = 0;  // Normal Mode
  US0_MR_bit.SMCARDPT = 0;  // Disable smart card protocol on USART
  US0_MR_bit.MODE9    = 0;  // The CHRL field defines the character length
  US0_MR_bit.CLKO     = 0;  // The USART does not drive the SCK pin
  // Set Baudrate
  // Baud = PCLK/(16*US0_BRGR)
  US0_BRGR = 11; // Baud 113636 Error 1.36%
  // Usart Rx and Tx enable
  US0_CR = (1<<4) | (1<<6);
  while(1)
  {
    // wait until character receiving
    if(US0_SR_bit.RXRDY)
    {
      // Get received character
      Int8U Data = US0_RHR;
      while(!US0_SR_bit.TXRDY);
      // Send asterisk
      US0_THR = '*';
      // wait until hold buffer is empty
      while(!US0_SR_bit.TXRDY);
      // send received character
      US0_THR = Data;
    }
  }
}