1: #include <pic.h>

     2: #include "hardware.h"

     3: #define __DEBUG

     4: void init_i2c(void)  {

     5:     char x ;

     6:     #ifdef __DEBUG

     7:     TRISB5=0;       // RA4 reflete l'état du dernier ACK du SONAR

     8:     RB5 = 0 ;

     9:     #define ACKLED RB5  

    10:     #endif

    11:     TRISC3 = 1 ; //SDA et SCL en entrée

    12:     TRISC4 = 1 ;

    13:     SSPSTAT = 0x80 ; // Pas de controle de slew rate, niveaux i2c

    14:     SSPCON = 0x28 ; // enable i2c 7bits master mode

    15:     SSPADD =  9 ; // fclock = 100khz = Fosc/(4(SSPADD+1)

    16:     x = SSPBUF ; // vide le buffer et raz flags

    17:    }

    18: 

    19: unsigned int read_compass(void)

    20:  {  

    21:     char bh,bl;

    22:     unsigned int b ;

    23:         SEN = 1;                                                // send start bit

    24:         while(SEN);                                     // and wait for it to clear

    25:         ACKDT = 0;                                      // acknowledge bit

    26:     

    27:     ACKSTAT=1;

    28:         SSPIF = 0;

    29:         SSPBUF = 0xC0;                          // C0 - write command

    30:         while(!SSPIF);                          // wait for interrupt

    31:         SSPIF = 0;

    32:     #ifdef __DEBUG                                      

    33:     ACKLED=ACKSTAT;

    34:     ACKSTAT=1;

    35:     #endif

    36:     SSPIF = 0;

    37:         SSPBUF = 0x02;                          // adress of cmd register

    38:         while(!SSPIF);                          // wait for interrupt

    39:         SSPIF = 0;      

    40:      #ifdef __DEBUG                                     

    41:     ACKLED=ACKSTAT;

    42:     ACKSTAT=1;

    43:     #endif

    44:         PEN = 1;                                                // send stop bit

    45:         while(PEN);                                     //

    46: 

    47:    

    48:     SEN = 1;                                    // send start bit

    49:         while(SEN);                                     // and wait for it to clear

    50:         ACKDT = 0;                                      // acknowledge bit

    51:     

    52:     SSPIF = 0;

    53:         SSPBUF = 0xC1;                          // 11000001 - read command

    54:         while(!SSPIF);                          // wait for interrupt

    55:         SSPIF = 0;                                      // then clear it.

    56:                 

    57:         RCEN = 1;                                       // start receiving

    58:         while(!STAT_BF);                        // wait for data

    59:         bh = SSPBUF;            // and get it

    60:         ACKEN = 1;                                      // start acknowledge sequence

    61:         while(ACKEN);                           // wait for ack. sequence to end

    62:         

    63:     RCEN = 1;                                   // start receiving

    64:         while(!STAT_BF);                        // wait for data

    65:         bl = SSPBUF;            // and get it

    66:     ACKDT=1;                    // very important ??

    67:         ACKEN = 1;                                      // start acknowledge sequence

    68:         while(ACKEN);                           // wait for ack. sequence to end

    69:   

    70:     PEN = 1;                                            // send stop bit

    71:         while(PEN);                                     //

    72:      #ifdef __DEBUG                                     

    73:     ACKLED=1;

    74:      #endif  

    75: 

    76:     b = (bh<<8) + bl ;

    77:     

    78:     return b ;

    79:    

    80:   

    81: }