Lynxmotion Tech Support

/*----------------------------------------------------------------------*/
/* DualShock SPI bit defines */

#define DAT PORTBbits.RB0
#define CMD PORTBbits.RB1
#define SEL PORTBbits.RB2
#define CLK PORTBbits.RB3

#define DELAY 2   /* changed from 1 (Lynxmotion) to 2 for Pelican */

#define ClockHi 1
#define ClockLow 0

/* Mode Numbers
 * 41 --> Digital mode
 * 73 --> analog mode
 * F3 --> DS2 native mode
 *
 * data comes back [0x73, 0x5A, 0xFF, 0xFF, 0x80, 0x80, 0x80, 0x80]
 */
/*----------------------------------------------------------------------*/
void ShiftStringOut(char *StrOutPtr, char *StrInPtr, unsigned char Length)

/*
 * Routine to shift out a number of PS2 SPI command bytes and
 * simultaneously read back responses.
 *
 * call with pointer to string of CMD bytes (StrOutPtr) and number of
 * command bytes in Length.
 *
 * Returns data in StrInPtr.
 * 08/09/07 alm
 */
   {
   unsigned int i;

   SEL = 0;               /* Select Controller */
   delayMicrosec(20);         /* initial "wakeup" */

   for(i = 0; i < Length; i++)
      {
      *StrInPtr++ = ShiftInOut(*StrOutPtr++);
      delayMicrosec(40);      /* between cmd bytes  */
      }

   SEL = 1;               /* Deselect Controller */

   delayMicrosec(50);         /* between cmd delay (need?) */
   }


/*----------------------------------------------------------------------*/
unsigned char ShiftInOut(unsigned char SendChr)

/*
 * Routine to send commands and receive data from PS2 via SPI
 * Shift out (LSB first) a byte to SPI
 * and simultaneously shift in (LSB first) a byte
 *
 * Call with byte to send.
 * Returns byte read.
 *
 * 09/02/07 data changes *BEFORE* negative going clock edges
 *
 * Observed 312K clock rate, 1 uS clock pulse width
 */

   {
   unsigned char i, mask;
   unsigned char RcvChr;

   RcvChr = 0;
   CMD = 1;   

   for(i = 0, mask = 1; i < 8; i++, mask <<= 1)
      {
      if(SendChr & mask)   /* output a data bit */
         CMD = 1;
      else
         CMD = 0;

      CLK = ClockLow;      /* generate 1 uS clock pulse */

      delayMicrosec(DELAY);

      CLK = ClockHi;      /* Clock the Bit */

      if(DAT)         /* input a data bit */
           RcvChr |= mask;
      else
           RcvChr &= ~mask;   /* for balance of inst time */

      delayMicrosec(DELAY);
      }

   CMD = 1;

   return(RcvChr);
   }

/*--------------------------------------------------------------------*/
void PS2_SPItest(void)

/*
 * Test Loop Function for PS2 routines
 */

  {
  int i, j, loc;
  unsigned char data[9];
  unsigned char cmd[9] =
   {0x01, 0x42, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

   do
   {
   i = 9;   /* end of the list */

   ShiftStringOut(cmd, data, i);

/* print the data, start with mode (data[0] is ignored) */
/* use last index to stop at */

   for(loc = 0, j = 1; j < i; j++)
      loc += sprintf(&buff[loc], "%02X ", data[j]);

   sprintf(&buff[loc], "\r\n");
   PutString(buff);

   for(i = 0; i < 40; i++)      /* 10 mS */
      delayMicrosec(250);
   }
   while(1);

  }

/*----------------------------------------------------------------------*/