关于AD采集电压的问题

#include <adc.h>

#include <stdint.h>

#include <stdbool.h>

#include <xc.h>



#include <adc.h>



#define PIN_ANALOG    1

#define PIN_DIGITAL   0



#define PIN_INPUT     1

#define PIN_OUTPUT    0



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

* Function: ADC_ReadPercentage(ADC_CHANNEL channel);

*

* Overview: Reads the requested ADC channel and returns the percentage 

*            of that conversions result (0-100%).

*

* PreCondition: channel is configured via the ADCConfigure() function

*

* Input: ADC_CHANNEL channel - enumeration of the ADC channels

*        available in this demo.  They should be meaningful names and 

*        not the names of the ADC pins on the device (as the demo code 

*        may be ported to other boards).

*         i.e. ADC_ReadPercentage(ADC_CHANNEL_POTENTIOMETER);

*

* Output: uint8_t indicating the percentage of the result 0-100% or

*         0xFF for an error

*

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

uint8_t ADC_ReadPercentage

    (ADC_CHANNEL channel) {

    uint8_t percent;



    switch(channel)

    {

        case ADC_CHANNEL_0:

            break;

        default:

            return 0xFF;

    }

    

    //A very crude percentage calculation

    percent = (ADC_Read10bit(channel) / 10);



    if(percent > 100)

    {

        percent = 100;

    }

    return percent;

}



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

* Function: ADC_Read10bit(ADC_CHANNEL channel);

*

* Overview: Reads the requested ADC channel and returns the 10-bit

*           representation of this data.

*

* PreCondition: channel is configured via the ADCConfigure() function

*

* Input: ADC_CHANNEL channel - enumeration of the ADC channels

*        available in this demo.  They should be meaningful names and

*        not the names of the ADC pins on the device (as the demo code

*        may be ported to other boards).

*         i.e. - ADCReadPercentage(ADC_CHANNEL_POTENTIOMETER);

*

* Output: uint16_t the right adjusted 10-bit representation of the ADC

*         channel conversion or 0xFFFF for an error.

*

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

uint16_t ADC_Read10bit(ADC_CHANNEL channel)

{

    uint16_t result;



    switch(channel)

    {

        case ADC_CHANNEL_0:

            break;

        default:

            return 0xFFFF;

    }



    ADCON0bits.CHS = channel;



    ADCON0bits.GO = 1;              // Start AD conversion

    while(ADCON0bits.NOT_DONE);     // Wait for conversion



    result = ADRESH;

    result <<=8;

    result |= ADRESL;



    return result;

}



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

* Function: bool ADC_Enable(ADC_CHANNEL channel, ADC_CONFIGURATION configuration);

*

* Overview: Configures the ADC module to specified setting

*

* PreCondition: none

*

* Input: ADC_CHANNEL channel - the channel to enable

*        ADC_CONFIGURATION configuration - the mode in which to run the ADC

*

* Output: bool - true if successfully configured.  false otherwise.

*

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

bool ADC_Enable(ADC_CHANNEL channel)

{

    switch(channel)

    {

        case ADC_CHANNEL_0:

            TRISAbits.TRISA0 = PIN_INPUT;

            ANCON0bits.PCFG0 = PIN_ANALOG;

            return true;



        default:

            return false;

    }

}



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

* Function: bool ADC_SetConfiguration(ADC_CONFIGURATION configuration)

*

* Overview: Configures the ADC module to specified setting

*

* PreCondition: none

*

* Input: ADC_CONFIGURATION configuration - the mode in which to run the ADC

*

* Output: bool - true if successfully configured.  false otherwise.

*

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

bool ADC_SetConfiguration(ADC_CONFIGURATION configuration)

{

    if(configuration == ADC_CONFIGURATION_DEFAULT)

    {

        ADCON0=0x01;

        ADCON1=0x9E;

        

        return true;

    }



    return false;

}