//*****************************************************************************
//  
//  MSP-FET430P140 FET Board equipped with MSP430FW42x, with daughtercard 
//  equipped with two GMR sensors
//
//  Description; Detect rotation of a disc using the Scan IF module of the 'FW.
//               Rotation is indicated using four LEDs that cycle a binary 
//               count for each half-rotation. 
//
//  Note: When using the daughtercard with the MSP-FETP140 remove jumper J6.
//
//
//                MSP430FW42x
//             -----------------
//         /|\|              XIN|-
//          | |                 | 32.768kHz
//          --|RST          XOUT|-
//            |                 |
//            |             P6.4|-->LED 1
//     GMR1-->|SIFCH0           |
//            |             P6.5|-->LED 2
//     GMR2-->|SIFCH1           |
//            |             P6.6|-->LED 3
//            |                 |
//            |             P6.7|-->LED 4
//
//  K. Quiring
//  Texas Instruments, Inc
//  August 2006
//
//  Based on code written for LC sensors, by  C. Hernitscheck / Z. Albus
//*****************************************************************************
#include "msp430xw42x.h"

extern void InitScanIF(void);
extern void SIFCalib(void);

const unsigned char PSM[] = {
                              0x00,  // No rotation
                              0x41,  // Error
                              0x0A,  // Next step counter-clockwise (+1)
                              0x49,  // Error
                              0x00,  // Next step counter-clockwise
                              0x01,  // No rotation
                              0x48,  // Error
                              0x49,  // Error
                              0x10,  // Next step counter-clockwise
                              0x41,  // Error
                              0x08,  // No rotation
                              0x49,  // Error
                              0x40,  // Error
                              0x41,  // Error
                              0x48,  // Error
                              0x49,  // Error
                              0x10,  // No rotation
                              0x01,  // Next step counter-clockwise
                              0x48,  // Error
                              0x49   // Error
                            };

volatile unsigned int i,j,k;

// Storage used in PSM state tracking function
char v=1,w=0,x=0,y=0,z=0;
char stateList[0x300];
int stateListIndex = 0;

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Disable Watchdog
  FLL_CTL0 |= XCAP18PF;                     // Configure load caps

  while(FLL_CTL0 & LFOF);                   // Wait until LF OSC stabilizes
    
  P1DIR = 0xFF;                             // Configure unused outputs
  P2DIR = 0xFF;                             // Configure unused outputs
  P3DIR = 0xFF;                             // Configure unused outputs
  P4DIR = 0xFF;                             // Configure unused outputs
  P5DIR = 0xFC;                             // Configure unused outputs
  P6OUT = 0x00;                             // P6.4-6.7 drive LEDs
  P6DIR = 0xF0;                             // P6.4-6.7 drive LEDs
  P6SEL |= 0x03;                            // Activate SIFCH0/1 (P6.0/1)
  
  SIFCalib();                               // Calibration of DAC thresholds
  
  // Flash LEDs to signal end of calibration.  When 
  // the lights go out, S2/S1 outputs need to read "00"
  P6OUT = 0x00;
  for(j=0x07;j>0;j--)
    for(i=0x3FFF;i>0;i--);
  for(k=0x04;k>0;k--)
  {
    P6OUT = 0xF0;
    for(j=0x03;j>0;j--)
      for(i=0x27FF;i>0;i--);
    P6OUT = 0x00;
    for(j=0x03;j>0;j--)
      for(i=0x27FF;i>0;i--);
  }
  
  InitScanIF();                             // Initialization of ScanIf module
  _EINT();


  // In normal operation, the code would be configured to enter LPM3.  During 
  // debug, the PSM tracking function below can be used to track PSM state 
  // transitions.  This can reveal problems in the PSM, as well as identify the
  // specific S2/S1 transition that occurred before any error.  If the LPM3
  // line below is commented out, the tracking function will run continuously
  // during SIF operation.  If uncommented, the device will enter LPM3 and 
  // execution will not reach the tracking function.  

  _BIS_SR(LPM3_bits + GIE);                 // Leave uncommented if not 
                                            // tracking PSM
  
  // Loop endlessly, capturing all PSM state transitions to array stateList[]. 
  // Runs about every 12us.  
  SIFDEBUG = 0x0000;
  while(1)
  {
    w = v;
    v = (char) SIFDEBUG & 0x00FF;

    if(!(v==w))
    {
      stateList[stateListIndex++] = v;
      if (stateListIndex > 0x2FF)           //In case stateList runs past 0x2FF
        stateListIndex = 0;
    }
  }  
} // End Main

#pragma vector=SCANIF_VECTOR
  __interrupt void ISR_ScanIF(void)
{
  if(SIFCTL1&SIFIFG3)
  {
    P6OUT = SIFCNT << 4;                    // Display LSBs with LEDs
    SIFCTL1 &= ~0x0060;
  }
    
  if(SIFCTL1&SIFIFG5)
    SIFCTL1 &= ~SIFIFG5;                    // Breakpoint here to catch errors
  
  if((SIFCTL1&SIFIE1)&&(SIFCTL1&SIFIFG1))
  {
     SIFCTL1 &= ~SIFIFG1;
     _BIC_SR_IRQ(LPM3_bits);                // Exit LPM3 after reti
  }
}

void InitScanIF(void)
{
  // Use the same TSM that was defined in SIFCalib(), so no settings made here

  SIFCTL4 = SIFCNT1ENP+SIFDIV3_14;     // CNT1 incr enabled, no decr; 
                                       // SIFCLK = ACLK/14
  SIFPSMV = (unsigned int) &PSM;       // Initialize PSM for main operation
  SIFCTL1 = SIFIE5+SIFIE3+SIFEN;       // SIF_EN=1; int on cntr incr and on err
}