#include "msp430x20x1.h"
#define PERIOD 64
#define MAX_THRESH PERIOD
#define MIN_THRESH 0
#define DELTA 1
#define LED_COUNT 8
void main(void)
{
  int i, j;
  unsigned char dir[] = {1, 1, 1, 1, 1, 1, 1, 1};
  unsigned char p1_value;
  int threshold[] = {
    0,
    PERIOD / LED_COUNT,
    2 * PERIOD / LED_COUNT,
    3 * PERIOD / LED_COUNT,
    4 * PERIOD / LED_COUNT,
    5 * PERIOD / LED_COUNT,
    6 * PERIOD / LED_COUNT,
    7 * PERIOD / LED_COUNT
  };

  WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
  P1DIR = 0xFF;

  while (1)
  {
    for (i = 0; i < PERIOD; i++)
    {
      int mask = 1;
      for (j = 0; j < LED_COUNT; ++j)
      {
        if (i > threshold[j])
        {
          p1_value &= ~mask;
        }
        else
        {
          p1_value |= mask;
        }
        mask <<= 1;
      }
      P1OUT = p1_value;
    }

    // Update thresholds and directions.
    for (j = 0; j < LED_COUNT; ++j)
    {
      if (dir[j])
      {
        threshold[j] += DELTA;
      }
      else
      {
        threshold[j] -= DELTA;
      }
      if (threshold[j] >= MAX_THRESH)
      {
        dir[j] = 0;
      }
      else if (threshold[j] <= MIN_THRESH)
      {
        dir[j] = 1;
      }
    }
  }
}