i2c_master.c

MSP430和GPS的接口程序

//******************************************************************************
//
//                                 /|\  /|\
//                  MSP430F169     5k   5k     MSP430F169
//                    slave         |    |        master
//              -----------------|  |    |  -----------------
//       8Mhz--|XT2IN        P2.0|<-|----+>|P3.1             |
//             |XT2OUT           |  |      |                 |
//             |                 |  |      |              XIN|-- 32768 Hz
//    32768Hz--|XIN          P1.0|<-+----->|P3.3         XOUT|--
//             |XOUT             |         |                 |
//
//
//******************************************************************************
#include  <msp430x16x.h>

#define UART_TX_RETRY   10000

//#define DELTA 900                         // target DCO = DELTA*(4096) = 3686400
#define DELTA 244                           // target DCO = DELTA*(4096) = 1048576
//#define DELTA 70                          // target DCO = DELTA*(4096) = 286720

#define DCO_FREQ        ((double)DELTA * 4096)      // DCO frequency
#define UART_BAUD_RATE  9600                // Baud Rate


#define DEBOUNCE_CNT    20
#define I2C_ADDR        0x23


#define EVENT_SW1       0x01
#define EVENT_SW2       0x02
#define EVENT_INT       0x04


//
// I2C Message Identifiers
//
#define SET_RTC_PARAMS       0
#define GET_RTC_PARAMS       1
#define SEND_IR_DATA         2
#define GET_LAST_IR_VALUE    3
#define GET_INPUT_STATE      4
#define GET_EVENT            5


//
// Event Flags for I2C getEvent message
//
#define EVENT_STATE_CHG      0x01           // Input signal state change
#define EVENT_IR_DATA        0x02           // IR data ready


void sysInit(void);
void setDCO(void);
void configUart1(void);
void configI2C(void);
void configWDT(void);
void iicSend(unsigned char addr, unsigned char bytes, unsigned char rwflag);
void sw1Options(void);
void sw2Options(void);
void txStr(const char* pStr);
void txByte(unsigned char byte);
void txWord(unsigned int word);
void setRTC(void);
void getRTC(void);
void getIRData(void);
void getIRVal(void);
void getInputState(void);
void getEvent(void);



unsigned char rxMsgLen;
unsigned char debounceCnt[3];
unsigned char Event = 0;
unsigned char rxIdx;
unsigned char RX_DATA[32];
unsigned char txIdx;
unsigned char TX_DATA[32];


//
//  Low-level system initialization - called prior to main()
//
int __low_level_init(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  return (1);                               // Force initialization of RAM
  //  return (0);                           // Skip initialization of RAM
}


//
// Set DCO to selected frequency
//
void setDCO(void)
{
  unsigned int Compare, Oldcapture = 0;

  BCSCTL1 |= DIVA_3;                        // ACLK= LFXT1CLK/8
  CCTL2 = CM_1 + CCIS_1 + CAP;              // CAP, ACLK
  TACTL = TASSEL_2 + MC_2 + TACLR;          // SMCLK, cont-mode, clear

  while(1)
  {
    while (!(CCIFG & CCTL2));               // 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)
      {
        if (!(BCSCTL1 == (XT2OFF + DIVA_3)))
        BCSCTL1--;                          // Did DCO roll under?, Sel lower RSEL
      }
    }
    else
    {
      DCOCTL++;
      if (DCOCTL == 0x00)
        {
          if (!(BCSCTL1 == (XT2OFF + DIVA_3 + 0x07)))
          BCSCTL1++;                        // Did DCO roll over? Sel higher RSEL
        }
    }
  }

  CCTL2 = 0;                                // Stop CCR2
  TACTL = 0;                                // Stop Timer_A
}


//
//  System Initialization
//
void sysInit(void)
{
  setDCO();                                 // Set DCO

  P1IES |=  0x30;                           // Set P1.5,4 for 1->0 interrupt
  P1IFG  =  0x00;                           // Clear P1 interrupt flags
  P1IE  |=  0x30;                           // Enable P1.5,4 interrupts

  P5DIR |= 0x70;                            // P5.6,5,4 outputs
  P5SEL |= 0x70;                            // P5.6,5,4 options

  P2OUT = 0x00;
  P2IES &= ~0x01;                           // Enable P2.0 interrupt
  P2IFG &= ~0x01;                           // Enable P2.0 interrupt
  P2IE  |=  0x01;                           // Enable P2.0 interrupt

  configI2C();

  configUart1();

  configWDT();
}


void configI2C(void)
{
  P3SEL |= 0x0A;                            // Select I2C pins

  U0CTL = SWRST;                            // Recommended init procedure
  U0CTL |= I2C + SYNC;                      // Recommended init procedure
  U0CTL &= ~I2CEN;                          // Recommended init procedure
  I2COA = 0x30;                             // OWN ADDRESS
  I2CPSC = 0;
  I2CSCLH = 0;
  I2CSCLL = 0;
  I2CTCTL = I2CSSEL1+I2CRM;                 // SMCLK, repeat Mode
  U0CTL |= I2CEN;                           // Enable I2C
}


//
// Configure USART1 for UART mode
//
void configUart1(void)
{
  unsigned int rate;

  // Calculate Buad Rate Clock divider values
  rate = (DCO_FREQ/UART_BAUD_RATE);

  P3SEL |= 0xC0;                            // P3.7,6 = URXD1/UTXD1
  ME2 |= UTXE1 + URXE1;                     // Enable USART1 TXD/RXD
  U1CTL |= (CHAR + SWRST);                  // 8-bit char, reset
  U1TCTL |= SSEL1;                          // BRCLK = SMCLK
  U1BR0 = (unsigned char)(rate & 0xff);     // Lower 8 bits of BR clk divider
  U1BR1 = (unsigned char)(rate >> 8);       // Upper 8 bits of BR clk divider
  U1MCTL = 0;                               // Modulation
  U1CTL &= ~SWRST;                          // Initialize USART state machine
  IE2 |= URXIE1;                            // Enable USART1 RX interrupt
}


//
// Configure Watchdog Timer
//
void configWDT(void)
{
  WDTCTL = WDT_ADLY_1_9;                    // Clk source is ACLK,
                                            // interval timer mode,
                                            // clear, divide by 32768
}


//
// I2C Send
//
void iicSend(unsigned char addr, unsigned char bytes, unsigned char rwflag)
{
  while( I2CDCTL & I2CBB ){}                // Wait for I2C bus to stop being busy

  if( rwflag )                              // Read
  {
    I2CIE = 0;                              // Disable I2C interrupts
    I2CIFG = 0;
    rxIdx = 0;                              // Reset buffer index
    I2CSA = addr;                           // Slave Address is 048h
    U0CTL &= ~I2CEN;                        // Recommended init procedure
    I2CTCTL = I2CSSEL1 + I2CRM;             // SMCLK, repeat Mode
    U0CTL |= I2CEN;                         // Enable I2C
    I2CIE = RXRDYIE;                        // Enable RXRDYIFG interrupt
    U0CTL |= MST;
    I2CTCTL |= I2CSTT;
  }
  else                                      // Write
  {
    I2CIE = 0;                              // Disable I2C interrupts
    I2CIFG = 0;
    txIdx = 0;                              // Reset buffer index
    I2CSA = addr;                           // Slave Address is 048h
    U0CTL &= ~I2CEN;                        // Recommended init procedure
    I2CTCTL = I2CSSEL1;                     // SMCLK
    U0CTL |= I2CEN;                         // Enable I2C

    I2CNDAT = bytes;                        // Set number of bytes to write
    I2CIE = TXRDYIE;                        // Enable I2C interrupts
    U0CTL |= MST;                           // Master
    I2CTCTL |= I2CTRX + I2CSTT + I2CSTP;    // Transmit, start, stop
  }
}


//
// Main
//
void main(void)
{
  unsigned char x;

  // Initialize System
  sysInit();

  txStr("\x1b[2JI2C Master\r\n\n");

  while(1)
  {
    if( Event == 0 )
    {
      // Enter low-power mode 0 with interrupts enabled
      _BIS_SR(LPM0_bits + GIE);

      _NOP();
    }

    if( Event & EVENT_SW1 )
    {
      Event &= ~EVENT_SW1;                  // SW1 Event
      sw1Options();
    }

    if( Event & EVENT_SW2 )
    {
      Event &= ~EVENT_SW2;                  // SW2 Event
      sw2Options();
    }

    if( Event & EVENT_INT )
    {
      Event &= ~EVENT_INT;                  // Interrupt Event

      txStr("\r\n\n\nInt - Get Interrupt Event");
      getEvent();
      iicSend(I2C_ADDR, TX_DATA[0], 0);     // I2C write
      iicSend(I2C_ADDR, 0, 1);              // I2C read
      txStr("\r\nInterrupt Event:");
      for(x = 1; x < RX_DATA[0]; x++)
      {
        txStr(" ");
        txByte(RX_DATA[x]);
      }

      if( RX_DATA[2] & EVENT_STATE_CHG )
      {
        txStr("\r\nInt - Get Input Pin State");
        getInputState();
        iicSend(I2C_ADDR, TX_DATA[0], 0);     // I2C write
        iicSend(I2C_ADDR, 0, 1);              // I2C read
        txStr("\r\nPin State:");
        for(x = 1; x < RX_DATA[0]; x++)
        {
          txStr(" ");
          txByte(RX_DATA[x]);
        }
      }

      if( RX_DATA[2] & EVENT_IR_DATA )
      {
        txStr("\r\nInt - Get IR Data");
        getIRData();
        iicSend(I2C_ADDR, TX_DATA[0], 0);     // I2C write
        iicSend(I2C_ADDR, 0, 1);              // I2C read
        txStr("\r\nIR Data:");
        for(x = 1; x < RX_DATA[0]; x++)
        {
          txStr(" ");
          txByte(RX_DATA[x]);
        }
      }

      P2IFG &= ~0x01;                           // Enable P2.0 interrupt
      P2IE  |=  0x01;                           // Enable P2.0 interrupt

      if( P2IN & 0x01 )
      {
        Event |= EVENT_INT;                     // Interrupt Event
      }
    }
  }
}


//
// USART0 I2C Interrupt Service Routine
//
#pragma vector=USART0TX_VECTOR
__interrupt void I2C_IV (void)
{
  switch( I2CIV )
  {
  case 0x02: break;                         // ALIFG: n/a
  case 0x04:                                // NACKIFG: n/a
    break;
  case 0x06: break;                         // OAIFG: n/a
  case 0x08: break;                         // ARDYIFG: n/a
  case 0x0A:
    RX_DATA[rxIdx++] = I2CDRB;

    if( rxIdx == 1 )                        // RXRDYIFG
    {
      rxMsgLen = RX_DATA[0]-1;              // Save message length
    }

    if( --rxMsgLen == 0 )
    {
      I2CTCTL |= I2CSTP;
    }

    break;
  case 0x0C:                                // TXRDYIFG