i2cmstse95.c

来自「NXP产品LPC23XX的开发板的源文件」· C语言 代码 · 共 87 行

/*****************************************************************************
 *   i2cmst.c:  main C entry file for Philips LPC214x Family Microprocessors
 *
 *   Copyright(C) 2006, Philips Semiconductor
 *   All rights reserved.
 *
 *   History
 *   2005.10.01  ver 1.00    Prelimnary version, first Release
 *
******************************************************************************/
#include "LPC214x.h"                        /* LPC21xx definitions */
#include "type.h"
#include "irq.h"
#include "i2cse95.h"

extern volatile DWORD I2CCount;
extern volatile BYTE I2CMasterBuffer[BUFSIZE];
extern volatile DWORD I2CCmd, I2CMasterState;
extern volatile DWORD I2CReadLength, I2CWriteLength;

/*******************************************************************************
**   Main Function  I2CReadTemp()
*******************************************************************************/
DWORD I2CReadTemp(void)
{
    DWORD i;
    /* the example used to test the I2C interface is 
    a Philips's SE95 temp sensor. LPC214x is used a I2C
    master, the temp sensor is a I2C slave.
    
    the sequence to get the temp reading is: 
	get device ID register,
	set configuration register,
	get temp reading

    In order to start the I2CEngine, the all the parameters 
    must be set in advance, including I2CWriteLength, I2CReadLength,
    I2CCmd, and the I2cMasterBuffer which contains the stream
    command/data to the I2c slave device. */

    /* Get device ID register */
    for ( i = 0; i < BUFSIZE; i++ )	/* clear buffer */
    {
		I2CMasterBuffer[i] = 0;
    }
    I2CWriteLength = 1;
    I2CReadLength = 1;
    I2CMasterBuffer[0] = SE95_ADDR;
    I2CMasterBuffer[1] = SE95_ID;
    I2CMasterBuffer[2] = SE95_ADDR | RD_BIT;
    I2CCmd = GET_DEVICE_ID;
    I2CEngine(); 

    /* Configure temp register before reading */
    for ( i = 0; i < BUFSIZE; i++ )	/* clear buffer */
    {
		I2CMasterBuffer[i] = 0;
    }
    I2CWriteLength = 2;
    I2CReadLength = 0;
    I2CMasterBuffer[0] = SE95_ADDR;
    I2CMasterBuffer[1] = SE95_CONFIG;
    I2CMasterBuffer[2] = 0x00;		/* configuration value, no change from default */
    I2CCmd = SET_CONFIGURATION;
    I2CEngine(); 

    /* Get temp reading */
    for ( i = 0; i < BUFSIZE; i++ )	/* clear buffer */
    {
		I2CMasterBuffer[i] = 0;
    }
    I2CWriteLength = 1;
    I2CReadLength = 2;
    I2CMasterBuffer[0] = SE95_ADDR;
    I2CMasterBuffer[1] = SE95_TEMP;
    I2CMasterBuffer[2] = SE95_ADDR | RD_BIT;
    I2CCmd = GET_TEMPERATURE;
    I2CEngine();

    /* The temp reading value should reside in I2CMasterBuffer byte 3, 4, ... */ 
    return 0;
}

/******************************************************************************
**                            End Of File
******************************************************************************/