ads1118驱动分享--EXP430G2

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/*

 * main.c

 *

 * MSP-EXP430G2-LaunchPad (v1.5+) User Experience Application for

 *      Communication to ADS1118

 *

 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/

 *

 *

 *  Redistribution and use in source and binary forms, with or without

 *  modification, are permitted provided that the following conditions

 *  are met:

 *

 *    Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 *

 *    Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the

 *    distribution.

 *

 *    Neither the name of Texas Instruments Incorporated nor the names of

 *    its contributors may be used to endorse or promote products derived

 *    from this software without specific prior written permission.

 *

 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

*/





/******************************************************************************

 * MSP-EXP430G2-LaunchPad User Experience Application for Communication to ADS1118

 *

 * 1. Program uses GRACE configuration for Device Configuration;

 *                 - SMCLK, ACLK, DCO at 1MHz

 *                 - USCIA0 as UART, 9600, 8 bits Data, No parity, 1 Stop (Hardware Mode)

 *                 - USCIB0 as 3 line SPI, Master Mode, 50kHz SCLK

 *                 - P2.0 used as CS for ADS1118 ADC device

 *

 * 2. Application Mode

 *           - Initial start configures device on power up

 *           - Configures connected ADS1118 device for differential measurement

 *                   pairs of AIN0-AIN1 and AIN2-AIN3

 *           - Data is transmitted in continuous loop

 *           - Runs ADS1118 in single shot mode reading first pair, changing mux and then

 *                   second pair storing data in a data array

 *           - After data is read, data is sent out UART for display as ASCII hex representation

 *

 * Changes:

 * 1.0  Initial Release Version

 *

 * Texas Instruments, Inc.

 ******************************************************************************/







/*

 * ======== Standard MSP430 includes ========

 */

#include <msp430g2553.h>



/*

 * ======== Grace related includes ========

 */

#include <ti/mcu/msp430/csl/CSL.h>





/*

 *  ======== Function Calls ========

 */



void uart_txc(char c);

void uart_txstr(char *c);

/* "hex2asc" Converts a 32-bit integer n into an ASCII string.



digs is the maximum number of digits to display.  Conversion is controlled

by mode, as follows:



- mode = 0: Leading zeroes are not printed.  The string may be

  less than digs digits long.

- mode = 1: Spaces are printed in place of leading zeroes.  The

  string will be digs digits long.

- mode = 2: Leading zeroes are printed.  The string will be digs

  digits long.



If the number is zero, at least one zero is printed in all modes.



This routine works by converting n to an 8-byte BCD number and calling

hex2asc.  No division by 10 is performed.

*/



int hex2asc(void *n, int digs, int mode, char *s);



void ADS_Config(void);

void ADS_Read(int data[]);

void Send_Result(int *data);

void Port_Config(void);

signed int WriteSPI(unsigned int config, int mode);

void delay(void);



#define h2a(d) ((d>9)?(d+'A'-10):(d+'0'))

#define LITTLEENDIAN 1



/*

 *  ======== main ========

 */

int main(int argc, char *argv[])

{

    CSL_init();                     // Activate Grace-generated configuration

    

    // >>>>> Fill-in user code here <<<<<



    // Initialize TC data array



    signed int data[6];



    // Port configuration

    Port_Config();



    // Set ADS1118 configuration

    ADS_Config();

    while (1)

    {

            // Read the data from both input pairs

            ADS_Read(data);





            // Transmit the data out the UART

            Send_Result(data);

    }





    return (0);

}



void Port_Config(void)

{

        // Set P1.0, P1.3, P1.4, P2.1, P2.2, P2.4, P2.5, P2.6 and P2.7 low



        P1OUT = 0x00;

        P2OUT = 0x01 ;

}





/*

 * Initial configuration routine.  A header file could be created, but the configuration is really rather simple.

 * In this case a 16-bit value representing the register contents is set to variable temp

 */

void ADS_Config(void)

{

        int i;



        unsigned int temp;



        // Set the configuration to AIN0/AIN1, FS=+/-1.024, SS, DR=128sps, PULLUP on DOUT

        temp = 0x78A;





        // Set CS low and write configuration

        P2OUT &= ~BIT0;





        // Write the configuration

        WriteSPI(temp,0);



        // Set CS high to end transaction

        P2OUT |= BIT0;

}







void ADS_Read(int data[])

{

        unsigned int j, temp;



        // Set the configuration to AIN0/AIN1, FS=+/-1.024, SS, DR=128sps, PULLUP on DOUT

        temp = 0x78A;



        // Set CS low and write configuration

        P2OUT &= ~BIT0;



        // First the data is captured by writing to each device to take start a conversion for A0-A1

        WriteSPI(temp,1);



        // Set CS high to end transaction

        P2OUT |= BIT0;



                /*

                 * Now we pause slightly before reading the data, or it is possible to either poll the DOUT/DRDY or enable an interrupt

                 * where the DOUT/DRDY transition from high to low triggers a read.  In this case it is kept quite simple with a delay

                 */



        delay();                // May be needed depending on method



        // When we read the data we restart the conversion with new mux channel A2-A3

        temp = 0x378A;



        // Set CS low and write configuration

        P2OUT &= ~BIT0;



        // Read the earlier conversion result and set to the new configuration

        data[0] = WriteSPI(temp,1);



        delay();                // May be needed depending on method



        // Read second channel data

        data[1]=WriteSPI(temp,0);



        // Set CS high to end transaction

        P2OUT |= BIT0;





}





signed int WriteSPI(unsigned int config, int mode)

{

        signed int msb;

        unsigned int temp;

        char dummy;



        temp = config;



        if (mode==1) temp = config | 0x8000;        // if mode is set to 1, this command should initiate a conversion



/*

 * The process of communication chosen is to always send the configuration and read it back

 * this results in a four byte transaction.  The configuration is 16-bit (or 2 bytes) and is transmitted twice.

 *

 */

        while(!(UC0IFG&UCB0TXIFG));                // Make sure buffer is clear



        /*

         *  First time configuration is written

         */



        UCB0TXBUF = (temp >> 8 );                // Write MSB of Config

        while(!(UC0IFG&UCB0RXIFG));

        msb=UCB0RXBUF;                                        // Read MSB of Result



        while(!(UC0IFG&UCB0TXIFG));



        UCB0TXBUF= (temp & 0xff);                // Write LSB of Config

        while(!(UC0IFG&UCB0RXIFG));

        msb = (msb << 8) | UCB0RXBUF ;        //Read LSB of Result



        /*

         * Second time configuration is written, although data could be sent as NOP in either transmission, just simplified in this case

         */



        while(!(UC0IFG&UCB0TXIFG));

        UCB0TXBUF = (temp >> 8 );                // Write MSB of Config



        while(!(UC0IFG&UCB0RXIFG));

        dummy=UCB0RXBUF;                                // Read MSB of Config



        /*

         * One advantage of reading the config data is that DOUT/DRDY is forced high which makes it possible to either poll the state or set an interrupt

         */

        while(!(UC0IFG&UCB0TXIFG));

        UCB0TXBUF= (temp & 0xff);                // Write LSB of Config



        while(!(UC0IFG&UCB0RXIFG));

        dummy=UCB0RXBUF;                                //Read LSB of Config





        return msb;

}









/*

 * Following code relates to formatting the data for transmission on UART

 */



void Send_Result(int *data)

{

        unsigned int i;

        int intval = 0;

        char char_array[5];



        // Poke out data

        uart_txstr("TEMPS:");

        uart_txc('\r');

        uart_txc('\n');

        for (i=0; i<2; i++)

        {

                intval = data[i];

                hex2asc(&intval, 4, 2, char_array);

                uart_txstr(char_array);

                uart_txc('\r');

                uart_txc('\n');

        }

}











int hex2asc(void *npos, int digs, int mode, char *s)

{

        int i,zero;

        char dig;

        char *spos=s;

        char *n=(char *)npos;



        zero=1;

#if LITTLEENDIAN

        n+=(digs-1)>>1;

#else

        n+=(16-digs)>>1;

#endif

        for (i=digs-1;i>=0;--i) {

                if (i&1) {

                        dig=(*(char *)n>>4)&15;

                } else {

                        dig=*(char *)n&15;

#if LITTLEENDIAN

                        --n;

#else

                        ++n;

#endif

                }

                if (zero&&dig)

                        zero=0;

                if (zero) {

                        switch(mode) {

                        case 1:

                                *spos++=' ';

                                break;

                        case 2:

                                *spos++='0';

                                break;

                        default:

                                break;

                        }

                } else

                        *spos++=h2a(dig);

        }

        if (zero&&mode==1)

                *(spos-1)='0';

        else if (zero&&mode==0)

                *spos++='0';

        *spos=0;

        return spos-s;

}

void uart_txc(char c)

{

        while (!((UC0IFG&UCA0TXIFG)));

        UCA0TXBUF=c;



}



void uart_txstr(char *c)

{

        while (*c) uart_txc(*(c++));

}



void delay(void)

{

        unsigned int k;



        for (k = 8000; k = 0; k--) __no_operation();



}

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