i2c.c

Philips LPC932 I2C 接口源程序

#include <reg922.h>
#include "i2cexprt.h"
#define PCF8574A_WR 0x70 /* i2c address */
idata char hello[] = "LPC2 - I2C test March 2002\n";
static bit second = 0; /* one second passed flag */
static WORD count;
static BYTE iopBuf[1];
static I2C_MESSAGE iopMsg;
static void UART_Init(void)
{
    P1M1 &= 0xFE;
    P1M2 |= 0x01;
    BRGR1 = 0x01;
    BRGR0 = 0x70;
    BRGCON = 3;
    SCON = 0x52; /* mode 1, receiver enable */
}
static void ua_outchar(char c)
{
    while (!TI) ;
    SBUF = c;
    TI = 0;
}
void PrintString( char *s)
{
    while (*s)
    {
        if (*s == '\n')
        ua_outchar('\r');
        ua_outchar(*s);
        s++;
    }
}
// LPC2 - OSC = 7,373 MHz, PRE = 2
// reload_value = -OSC/(PRE*500Hz) = -7373 = 2 msec
void T0_Interrupt(void) interrupt 1
{
    TR0 = 0; /* Stop timer 0 */
    TL0 = 0x33; /* set timer 0 reload value */
    TH0 = 0xe3;
    TR0 = 1; /* Restart timer 0 */
    if (++count > 500) /* 500 * 2 msec = 1 sec */
    {
    count = 0;
    second = 1; /* one second passed */
    }
}
static void T0_Init(void)
{
    count = 0;
    TMOD = 1; /* Timer 0 = Mode 1, 16 Bit */
    TL0 = 0x33; /* set timer 0 reload value */
    TH0 = 0xe3;
    ET0 = 1; /* enable timer 0 interrupt */
    TR0 = 1; /* start timer 0 */
}
static void RunLeds(void)
{
    static BYTE ioport;
    switch (ioport) /* run I2C IOport leds */
    {
        case 0x7f: ioport = 0xfe; break;
        case 0xbf: ioport = 0x7f; break;
        case 0xdf: ioport = 0xbf; break;
        case 0xef: ioport = 0xdf; break;
        case 0xf7: ioport = 0xef; break;
        case 0xfb: ioport = 0xf7; break;
        case 0xfd: ioport = 0xfb; break;
        case 0xfe: ioport = 0xfd; break;
        default: ioport = 0xfe; break;
    }
    iopBuf[0] = ioport;
    I2C_Write(&iopMsg);
}

void main(void)
{
    TRIM = 0x3C; /* clock out at P3.0 */
    T0_Init(); /* initialize Timer 0 */
    UART_Init(); /* initialize UART */
    I2C_Init(); /* initialize I2C bus */
    EA = 1; /* General interrupt enable */
    iopMsg.address = PCF8574A_WR;
    iopMsg.buf = iopBuf;
    iopMsg.nrBytes = 1;
    iopBuf[0] = 0xff;
    I2C_Write(&iopMsg);
    PrintString(hello);
    while (1)
    {
        if (second)
        {
        second = 0;
        Led = !Led; /* toggle the LED */
        RunLeds();
        }
    }
}