#include "config.h"
#include "io430x16x.h"
#ifndef EOF
   #define EOF (-1)
#endif

#ifndef USART0_RX_BUF_LEN
   #define USART0_RX_BUF_LEN (8)
#endif
#ifndef USART0_TX_BUF_LEN
   #define USART0_TX_BUF_LEN (8)
#endif

#define      enable_USART0_RX_interrupt     IE1 |=  URXIE0
//#define   disable_USART0_RX_interrupt     IE1 &= ~URXIE0
#define      enable_USART0_TX_interrupt     IE1 |=  UTXIE0
#define     disable_USART0_TX_interrupt     IE1 &= ~UTXIE0

static char rxput=0;
static char rxget=0;
static int  ungetcharacter = EOF;
static char rxbuf[USART0_RX_BUF_LEN];

static char txput=0;
static char txget=0;
static char txbuf[USART0_TX_BUF_LEN];


void U0_init (int div )
{
    rxput = rxget = txput = txget = 0;

    P3SEL |= (1<<4) | (1<<5); // sel P3.4 and P3.5 for USART0
    P3DIR |= (1<<4);  // TxD0, output
    P3DIR &=~(1<<5);  // RxD0, input
    ME1 |= URXE0 | UTXE0;

    U0CTL_bit.SWRST = 1;
    U0CTL_bit.CHAR  = 1; // 8 bit
    U0TCTL = (SSEL0 | SSEL1);
    //U0RCTL
    U0BR0 = div & 0xff;    U0BR1  = div >> 8;
    U0MCTL = 0;
    U0CTL_bit.SWRST = 0;
    enable_USART0_RX_interrupt;
}

/*
int U0_getchar (void)
{
    while( IFG1_bit.URXIFG0 != 1 )
    ;

    return U0RXBUF;
}


int U0_putchar (int ch)
{
    while( IFG1_bit.UTXIFG0 != 1 )
    ;
    return U0TXBUF = ch;
}

*/


#pragma vector = USART0RX_VECTOR
__interrupt void USART0_RX(void)
{
char i = rxput;

  rxbuf[i++] = U0RXBUF;
  if( i >= USART0_RX_BUF_LEN ) i=0;
  if( i != rxget ) rxput = i;

}

#pragma vector = USART0TX_VECTOR
__interrupt void USART0_TX(void)
{
  U0TXBUF = txbuf[txget++];
  if( txget >= USART0_TX_BUF_LEN )
     txget=0;
  if( txget == txput)
     disable_USART0_TX_interrupt;
}


int U0_getchar(void)
{
  if(ungetcharacter != EOF)
  {
     int i = ungetcharacter;
     ungetcharacter = EOF;
     return i;
  }
  if(rxget != rxput)
  {
     int i = rxbuf[rxget];
     if( rxget >= (USART0_RX_BUF_LEN-1) )
        rxget=0;
     else rxget++;
     return i;
  }
  else return EOF;
}

int U0_ungetc (int ch)
{
   return ungetcharacter = ch;
}

int U0_putchar (int ch)
{
char i=txput;

   if( ++i >= USART0_TX_BUF_LEN )  i = 0;
   if( i != txget )
   {
      txbuf[txput] = ch;
      txput = i;
      enable_USART0_TX_interrupt;
      return ch & 0xff;
   }
   else return EOF;
}

int U0_getcharw (void)
{
int i;
   while(EOF == (i=U0_getchar()))
   ;
   return i;
}

int U0_putcharw (int ch)
{
   while(EOF == U0_putchar(ch))
   ;
return ch;
}

void U0_gets (char *s, int len ) //= 10)
{
char c;
   for( ; --len; )
   {
      c = U0_getcharw();
      U0_putcharw(c);
      if( (c == '\n') || (c == '\r'))
         break;
      else
         *s++ = c;
   }
   *s = 0;
}

void U0_puts (char *s)
{
   while( *s )
      U0_putcharw( *s++ );
}