PICでI2Cを試す（マスター編）

/* 
 * File:   main.c
 * Author: sakai
 *
 * Created on 2015/05/16, 23:04
 */

#include <stdio.h>
#include <stdlib.h>
#include <xc.h>

#define _XTAL_FREQ  32000000

#pragma config FOSC = INTOSC  // INTOSCIO
#pragma config CLKOUTEN = OFF
#pragma config FCMEN = OFF
#pragma config IESO = OFF
#pragma config MCLRE = ON
#pragma config BOREN = ON   // Brown Out Detect
#pragma config WDTE = OFF
#pragma config CPD = OFF    // Data Code Protection bit
#pragma config CP = OFF
#pragma config PWRTE = ON
#pragma config PLLEN = OFF
#pragma config STVREN = ON
#pragma config WRT = OFF
#pragma config BORV = HI
#pragma config LVP = OFF

#define I2C_DEBUGGER_ADDRESS    (0x20)

#define I2C_IDLE_PORT   (PORTBbits.RB0)

#define MAX_BUFF    (32)

typedef unsigned char byte;

byte logging = 0;
byte data[MAX_BUFF];
byte dindex = 0;

static void interrupt intr(void) {
    // 割り込み
    if (SSPIF == 1) {
        if (logging) {
            data[dindex] = SSPSTAT;
            dindex++;
        }
        PORTAbits.RA5 = 1;
        SSPIF = 0; // クリア
    }
}

void i2c_idle() {
    while (SSPCON2bits.SEN || SSPCON2bits.RSEN || SSPCON2bits.PEN ||
           SSPCON2bits.RCEN || SSPCON2bits.ACKEN || SSPSTATbits.R_nW) {
        I2C_IDLE_PORT = 0;
    }
    I2C_IDLE_PORT = 1;
}

/*
 * 
 */
int main(int argc, char** argv) {
    OSCCON = 0b11110000;
    // A, Bポートの設定
    ANSELA = 0;
    ANSELB = 0;
    TRISA = 0b00000000;
    TRISB = 0b00000000;
    PORTA = 0b00000000;
    PORTB = 0b00000000;

    // I2Cマスターの設定
    SSPSTAT = 0b00000000;
    SSPCON1 = 0b00101000;   // SSPEN=1, SSPM<3:0>=FOSC/4*(SSPADD+1) SSPADD=19
    SSPCON2 = 0b00000000;
    SSPCON3 = 0b00000000;
    SSPADD  = 19;           // 400kHz

    // 割り込み
    PIE1    = 0b00001000;   // SSPIE=1
    PIE2    = 0b00001000;   // BCLIE=1
    PIE3    = 0b00000000;
    INTCON  = 0b11000000;   // GIE, PEIE

    PORTBbits.RB0 = 1;
    PORTBbits.RB1 = 1;
    PORTBbits.RB2 = 1;
    PORTBbits.RB3 = 1;
    PORTBbits.RB4 = 1;
    PORTBbits.RB5 = 1;
    PORTAbits.RA7 = 1;

    byte count = 0;
    logging = 1;

    i2c_idle();
    SSPCON2bits.SEN = 1;    // スタートコンディション
    while (SSPCON2bits.SEN) ;
    SSPBUF = I2C_DEBUGGER_ADDRESS<<1;
    while (SSPSTATbits.BF) ;
    while (SSPCON2bits.ACKSTAT) PORTAbits.RA7 = 1;
    PORTAbits.RA7 = 0;
    i2c_idle();
    SSPBUF = 0x00;
    while (SSPSTATbits.BF) ;
    while (SSPCON2bits.ACKSTAT) PORTAbits.RA7 = 1;
    PORTAbits.RA7 = 0;
    i2c_idle();
    SSPBUF = 0x88;
    while (SSPSTATbits.BF) ;
    while (SSPCON2bits.ACKSTAT) PORTAbits.RA7 = 1;
    PORTAbits.RA7 = 0;
    i2c_idle();
    SSPCON2bits.PEN = 1;    // ストップコンディション
    while (SSPCON2bits.PEN) ;

    logging = 0;
    for (count = 0; count < 45; count++) {  // 45秒待ち
        __delay_ms(1000);
    }

    i2c_idle();
    SSPCON2bits.SEN = 1;    // スタートコンディション
    while (SSPCON2bits.SEN) ;
    SSPBUF = I2C_DEBUGGER_ADDRESS<<1;
    while (SSPSTATbits.BF) ;
    while (SSPCON2bits.ACKSTAT) PORTAbits.RA7 = 1;
    PORTAbits.RA7 = 0;
    count = 0;
    while (count < dindex) {
        i2c_idle();
        SSPBUF = data[count];
        while (SSPSTATbits.BF) ;
        while (SSPCON2bits.ACKSTAT) PORTAbits.RA7 = 1;
        PORTAbits.RA7 = 0;
        count++;
    }
    i2c_idle();
    SSPCON2bits.PEN = 1;    // ストップコンディション
    while (SSPCON2bits.PEN) ;

    while (1) {
        PORTAbits.RA0 = 1;
        __delay_ms(50);
        PORTAbits.RA0 = 0;
        __delay_ms(50);
    }

    return (EXIT_SUCCESS);
}