nes-proj/cpu/msp430/msp430.c

/*
 * Copyright (c) 2005, Swedish Institute of Computer Science
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file is part of the Contiki operating system.
 *
 * @(#)$Id: msp430.c,v 1.7 2007/11/17 10:28:18 adamdunkels Exp $
 */
#include <io.h>
#include <signal.h>
#include <sys/unistd.h>
#include "dev/watchdog.h"
#include "net/uip.h"

/*---------------------------------------------------------------------------*/
void
msp430_init_dco(void)
{
    /* This code taken from the FU Berlin sources and reformatted. */
#define DELTA    600

  unsigned int compare, oldcapture = 0;
  unsigned int i;


  BCSCTL1 = 0xa4; /* ACLK is devided by 4. RSEL=6 no division for MCLK
		     and SSMCLK. XT2 is off. */

  BCSCTL2 = 0x00; /* Init FLL to desired frequency using the 32762Hz
		     crystal DCO frquenzy = 2,4576 MHz  */

  BCSCTL1 |= DIVA1 + DIVA0;             /* ACLK = LFXT1CLK/8 */
  for(i = 0xffff; i > 0; i--);          /* Delay for XTAL to settle */

  CCTL2 = CCIS0 + CM0 + CAP;            // Define CCR2, CAP, ACLK
  TACTL = TASSEL1 + TACLR + MC1;        // SMCLK, continous mode


  while(1) {

    while((CCTL2 & CCIFG) != CCIFG);    /* Wait until capture occured! */
    CCTL2 &= ~CCIFG;                    /* Capture occured, clear flag */
    compare = CCR2;                     /* Get current captured SMCLK */
    compare = compare - oldcapture;     /* SMCLK difference */
    oldcapture = CCR2;                  /* Save current captured SMCLK */

    if(DELTA == compare) {
      break;                            /* if equal, leave "while(1)" */
    } else if(DELTA < compare) {        /* DCO is too fast, slow it down */
      DCOCTL--;
      if(DCOCTL == 0xFF) {              /* Did DCO role under? */
	BCSCTL1--;
      }
    } else {                            /* -> Select next lower RSEL */
      DCOCTL++;
      if(DCOCTL == 0x00) {              /* Did DCO role over? */
	BCSCTL1++;
      }
                                        /* -> Select next higher RSEL  */
    }
  }

  CCTL2 = 0;                            /* Stop CCR2 function */
  TACTL = 0;                            /* Stop Timer_A */

  BCSCTL1 &= ~(DIVA1 + DIVA0);          /* remove /8 divisor from ACLK again */
}
/*---------------------------------------------------------------------------*/
static void
init_ports(void)
{
  /* Turn everything off, device drivers enable what is needed. */

  /* All configured for digital I/O */
#ifdef P1SEL
  P1SEL = 0;
#endif
#ifdef P2SEL
  P2SEL = 0;
#endif
#ifdef P3SEL
  P3SEL = 0;
#endif
#ifdef P4SEL
  P4SEL = 0;
#endif
#ifdef P5SEL
  P5SEL = 0;
#endif
#ifdef P6SEL
  P6SEL = 0;
#endif

  /* All available inputs */
#ifdef P1DIR
  P1DIR = 0;
  P1OUT = 0;
#endif
#ifdef P2DIR
  P2DIR = 0;
  P2OUT = 0;
#endif
#ifdef P3DIR
  P3DIR = 0;
  P3OUT = 0;
#endif
#ifdef P4DIR
  P4DIR = 0;
  P4OUT = 0;
#endif

#ifdef P5DIR
  P5DIR = 0;
  P5OUT = 0;
#endif

#ifdef P6DIR
  P6DIR = 0;
  P6OUT = 0;
#endif

  P1IE = 0;
  P2IE = 0;
}
/*---------------------------------------------------------------------------*/
/* msp430-ld may align _end incorrectly. Workaround in cpu_init. */
extern int _end;		/* Not in sys/unistd.h */
static char *cur_break = (char *)&_end;

void
msp430_cpu_init(void)
{
  dint();
  watchdog_stop();
  init_ports();
  msp430_init_dco();
  eint();
  if((uintptr_t)cur_break & 1) { /* Workaround for msp430-ld bug! */
    cur_break++;
  }
}
/*---------------------------------------------------------------------------*/
#define asmv(arg) __asm__ __volatile__(arg)

#define STACK_EXTRA 32

/*
 * Allocate memory from the heap. Check that we don't collide with the
 * stack right now (some other routine might later). A watchdog might
 * be used to check if cur_break and the stack pointer meet during
 * runtime.
 */
void *
sbrk(int incr)
{
  char *stack_pointer;

  asmv("mov r1, %0" : "=r" (stack_pointer));
  stack_pointer -= STACK_EXTRA;
  if(incr > (stack_pointer - cur_break))
    return (void *)-1;		/* ENOMEM */

  void *old_break = cur_break;
  cur_break += incr;
  /*
   * If the stack was never here then [old_break .. cur_break] should
   * be filled with zeros.
  */
  return old_break;
}
/*---------------------------------------------------------------------------*/
/*
 * Mask all interrupts that can be masked.
 */
int
splhigh_(void)
{
  /* Clear the GIE (General Interrupt Enable) flag. */
  int sr;
  asmv("mov r2, %0" : "=r" (sr));
  asmv("bic %0, r2" : : "i" (GIE));
  return sr & GIE;		/* Ignore other sr bits. */
}
/*---------------------------------------------------------------------------*/
/*
 * Restore previous interrupt mask.
 */
void
splx_(int sr)
{
  /* If GIE was set, restore it. */
  asmv("bis %0, r2" : : "r" (sr));
}
/*---------------------------------------------------------------------------*/