serial.c

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/******************************************************************************/
/*                                                                            */
/*  SERIAL.C:  Low Level Serial Routines                                      */
/*                                                                            */
/******************************************************************************/
/*  20080928: modify codes for ARM platform (NXP LPC2132)  */
/*  20071212: modify code for mcuzone's mp3 player use debug uart --by michael */
/* 
   10/2005 by Martin Thomas <[e-mail]>
   based on an example-code from Keil GmbH
   - modified for the WinARM example 
   - changed interface to avoid potential conflicts with "stdio.h"
*/

// included in board.h: #include <AT91SAM7S64.H> /* AT91SAMT7S64 definitions */
//#include "Board.h"
#include "global.h"

#define BR    115200ul                        /* Baud Rate */

//#define BRD  (MCK/16/BR)                    /* Baud Rate Divisor */


//AT91S_USART * pUSART = AT91C_BASE_US0;      /* Global Pointer to USART0 */
//AT91S_USART * pUSART = AT91C_BASE_DBGU;      /* Global Pointer to USART0 */

void uart0_init (void) {                   /* Initialize Serial Interface */

  uint16 Fdiv;
    
    PINSEL0 = (PINSEL0 & 0xfffffff0) | 0x05;    /* Select the pins for Uart 选择管脚为UART0 */

    U0LCR = 0x80;                               /* Enable to access the frequenc regecter 	
												允许访问分频因子寄存器 */
    Fdiv = (Fpclk / 16) / BR;                  /* Set the baudrate设置波特率 */
    U0DLM = Fdiv / 256;							
	U0DLL = Fdiv % 256;						
    U0LCR = 0x03;                               /* Disable to access the frequenc regecter 
												禁止访问分频因子寄存器 */
                                                /* set to 8,1,n 且设置为8,1,n */
	U0IER = 0x00;                               /* Disable interrupt禁止中断 */
    U0FCR = 0x00;                               /* initial FIFO 初始化FIFO */

#if 0
  /* mt: n.b: uart0 clock must be enabled to use it */

  //*AT91C_PIOA_PDR = AT91C_PA5_RXD0 |        /* Enable RxD0 Pin */
 //                   AT91C_PA6_TXD0;         /* Enalbe TxD0 Pin */

  *AT91C_PIOA_PDR = AT91C_PA9_DRXD |        /* Enable RxD0 Pin */
                    AT91C_PA10_DTXD;         /* Enalbe TxD0 Pin */

  pUSART->US_CR = AT91C_US_RSTRX |          /* Reset Receiver      */
                  AT91C_US_RSTTX |          /* Reset Transmitter   */
                  AT91C_US_RXDIS |          /* Receiver Disable    */
                  AT91C_US_TXDIS;           /* Transmitter Disable */

  pUSART->US_MR = AT91C_US_USMODE_NORMAL |  /* Normal Mode */
                  AT91C_US_CLKS_CLOCK    |  /* Clock = MCK */
                  AT91C_US_CHRL_8_BITS   |  /* 8-bit Data  */
                  AT91C_US_PAR_NONE      |  /* No Parity   */
                  AT91C_US_NBSTOP_1_BIT;    /* 1 Stop Bit  */

  pUSART->US_BRGR = BRD;                    /* Baud Rate Divisor */

  pUSART->US_CR = AT91C_US_RXEN  |          /* Receiver Enable     */
                  AT91C_US_TXEN;            /* Transmitter Enable  */
  #endif
}


int uart0_putc(int ch) 
{
	U0THR=ch;
	while((U0LSR&&0x40)==0);
	return 0;
#if 0
	while (!(pUSART->US_CSR & AT91C_US_TXRDY));   /* Wait for Empty Tx Buffer */
	return (pUSART->US_THR = ch);                 /* Transmit Character */
#endif
}	

int uart0_putchar (int ch) {                      /* Write Character to Serial Port */

  if (ch == '\n')  {                            /* Check for LF */
    uart0_putc( '\r' );                         /* Output CR */
  }
  return uart0_putc( ch );                     /* Transmit Character */
}

int uart0_puts ( char* s )
{
	int i = 0;
	while ( *s ) {
		uart0_putc( *s++ );
		i++;
	}
	return i;
}

int uart0_prints ( char* s )
{
	int i = 0;
	while ( *s ) {
		uart0_putchar( *s++ );
		i++;
	}
	return i;
}

int uart0_kbhit( void ) /* returns true if character in receive buffer */
{
#if 0
	if ( pUSART->US_CSR & AT91C_US_RXRDY) {
		return 1;
	}
	else {
		return 0;
	}
	#endif
return 0;
}

int uart0_getc ( void )  /* Read Character from Serial Port */
{   
#if 0
  while (!(pUSART->US_CSR & AT91C_US_RXRDY));   /* Wait for Full Rx Buffer */
  return (pUSART->US_RHR);                      /* Read Character */
#endif
return 0;
}

#define CR     0x0D
/* implementation of putchar (also used by printf function to output data)    */
int sendchar (int ch)  {                 /* Write character to Serial Port    */

  if (ch == '\n')  {
    while (!(U0LSR & 0x20));
    U1THR = CR;                          /* output CR */
  }
  while (!(U0LSR & 0x20));
  return (U0THR = ch);
}


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

  while (!(U0LSR & 0x01));

  return (U0RBR);
}