adc.c

ADC Input for ARM9 using KEIL.

/* ----------------------------------------------------------------------------
 *         ATMEL Microcontroller Software Support 
 * ----------------------------------------------------------------------------
 * Copyright (c) 2008, Atmel Corporation
 *
 * All rights reserved.
 *
 * 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 disclaimer below.
 *
 * Atmel's name may not be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
 * DISCLAIMED. IN NO EVENT SHALL ATMEL 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.
 * ----------------------------------------------------------------------------
 */

//------------------------------------------------------------------------------
//         Headers
//------------------------------------------------------------------------------

#include <board.h>
#include <adc/adc.h>
#include <utility/trace.h>
#include <utility/assert.h>

//-----------------------------------------------------------------------------
/// Configure the Mode Register of the ADC controller
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \param mode value to write in mode register
//-----------------------------------------------------------------------------
static void ADC_CfgModeReg(AT91S_ADC *pAdc, unsigned int mode)
{
    ASSERT((mode&0xF08000C0)== 0, "ADC Bad configuration ADC MR");

    // Clear the register
    pAdc->ADC_MR = 0;
    // Write to the MR register
    pAdc->ADC_MR = mode;
}

//------------------------------------------------------------------------------
//         Global Functions
//------------------------------------------------------------------------------

//-----------------------------------------------------------------------------
/// Initialize the ADC controller
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \param trgEn trigger mode, software or Hardware
/// \param trgSel hardware trigger selection
/// \param sleepMode sleep mode selection
/// \param resolution resolution selection 8 bits or 10 bits
/// \param mckClock value of MCK in Hz
/// \param adcClock value of the ADC clock in Hz
/// \param startupTime value of the start up time (in 祍) (see datasheet)
/// \param sampleAndHoldTime (in ns)
//-----------------------------------------------------------------------------
void ADC_Initialize (AT91S_ADC *pAdc,
                     unsigned char idAdc,
                     unsigned char trgEn,
                     unsigned char trgSel,
                     unsigned char sleepMode,
                     unsigned char resolution,        
                     unsigned int mckClock,
                     unsigned int adcClock,
                     unsigned int startupTime,
                     unsigned int sampleAndHoldTime)
{
    unsigned int prescal;
    unsigned int startup;
    unsigned int shtim;

    ASSERT(startupTime<=ADC_STARTUP_TIME_MAX, "ADC Bad startupTime\n\r");
    ASSERT(sampleAndHoldTime>=ADC_TRACK_HOLD_TIME_MIN, "ADC Bad sampleAndHoldTime\n\r");

    // Example:
    // 5 MHz operation, 20祍 startup time, 600ns track and hold time
    // PRESCAL: Prescaler Rate Selection ADCClock = MCK / ( (PRESCAL+1) * 2 )
    // PRESCAL = [MCK / (ADCClock * 2)] -1 = [48/(5*2)]-1 = 3,8
    // PRESCAL =  4 -> 48/((4+1)*2) = 48/10 = 4.8MHz
    // 48/((3+1)*2) = 48/8 = 6MHz
    // Startup Time = (STARTUP+1) * 8 / ADCClock
    // STARTUP = [(Startup Time * ADCClock)/8]-1 = [(20 10e-6 * 5000000)/8]-1 = 11,5
    // STARTUP = 11 -> (11+1)*8/48000000 = 96/4800000 = 20祍
    //
    // Sample & Hold Time = (SHTIM+1) / ADCClock
    // SHTIM = (HoldTime * ADCClock)-1 = (600 10e-9 * 5000000)-1 = 2
    // SHTIM   =  2 -> (2+1)/4800000 = 1/1200000 = 833ns
    prescal = (mckClock / (2*adcClock)) - 1;
    startup = ((adcClock/1000000) * startupTime / 8) - 1;
    shtim = (((adcClock/1000000) * sampleAndHoldTime)/1000) - 1;

    ASSERT( (prescal<0x3F), "ADC Bad PRESCAL\n\r");
    ASSERT(startup<0x7F, "ADC Bad STARTUP\n\r");
    ASSERT(shtim<0xF, "ADC Bad SampleAndHoldTime\n\r");

    TRACE_DEBUG("adcClock:%d MasterClock:%d\n\r", (mckClock/((prescal+1)*2)), mckClock);
    TRACE_DEBUG("prescal:0x%X startup:0x%X shtim:0x%X\n\r", prescal, startup, shtim);
    
    if( adcClock != (mckClock/((prescal+1)*2)) ) {
        TRACE_WARNING("User and calculated adcClocks are different : user=%d calc=%d\n\r", 
            adcClock, (mckClock/((prescal+1)*2)));
    }

    // Enable peripheral clock    
    AT91C_BASE_PMC->PMC_PCER = 1 << idAdc;    
    
    // Reset the controller
    ADC_SoftReset(pAdc);

    // Write to the MR register
    ADC_CfgModeReg( pAdc,
                    ( trgEn & AT91C_ADC_TRGEN)
                  | ( trgSel & AT91C_ADC_TRGSEL)
                  | ( resolution & AT91C_ADC_LOWRES)            
                  | ( sleepMode & AT91C_ADC_SLEEP)
                  | ( (prescal<<8) & AT91C_ADC_PRESCAL) 
                  | ( (startup<<16) & AT91C_ADC_STARTUP) 
                  | ( (shtim<<24) & AT91C_ADC_SHTIM) );
}

//-----------------------------------------------------------------------------
/// Return the Mode Register of the ADC controller value
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \return ADC Mode register
//-----------------------------------------------------------------------------
unsigned int ADC_GetModeReg(AT91S_ADC *pAdc)
{
    return pAdc->ADC_MR;    
}

//-----------------------------------------------------------------------------
/// Enable Channel
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \param channel channel to enable
//-----------------------------------------------------------------------------
void ADC_EnableChannel(AT91S_ADC *pAdc, unsigned int channel)
{
    ASSERT(channel < 8, "ADC Channel not exist");

    // Write to the CHER register
    pAdc->ADC_CHER = (1 << channel);
}

//-----------------------------------------------------------------------------
/// Disable Channel
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \param channel channel to disable
//-----------------------------------------------------------------------------
void ADC_DisableChannel (AT91S_ADC *pAdc, unsigned int channel)
{
    ASSERT(channel < 8, "ADC Channel not exist");

    // Write to the CHDR register
    pAdc->ADC_CHDR = (1 << channel);
}

//-----------------------------------------------------------------------------
/// Return chanel status
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \return ADC Channel Status Register
//-----------------------------------------------------------------------------
unsigned int ADC_GetChannelStatus(AT91S_ADC *pAdc)
{
    return pAdc->ADC_CHSR;    
}

//-----------------------------------------------------------------------------
/// Software request for a analog to digital conversion 
/// \param pAdc Pointer to an AT91S_ADC instance.
//-----------------------------------------------------------------------------
void ADC_StartConversion(AT91S_ADC *pAdc)
{
    pAdc->ADC_CR = AT91C_ADC_START;    
}

//-----------------------------------------------------------------------------
/// Software reset
/// \param pAdc Pointer to an AT91S_ADC instance.
//-----------------------------------------------------------------------------
void ADC_SoftReset(AT91S_ADC *pAdc)
{
    pAdc->ADC_CR = AT91C_ADC_SWRST;    
}

//-----------------------------------------------------------------------------
/// Return the Last Converted Data
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \return Last Converted Data
//-----------------------------------------------------------------------------
unsigned int ADC_GetLastConvertedData(AT91S_ADC *pAdc)
{
    return pAdc->ADC_LCDR;    
}

//-----------------------------------------------------------------------------
/// Return the Channel Converted Data
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \param channel channel to get converted value
/// \return Channel converted data of the specified channel
//-----------------------------------------------------------------------------
unsigned int ADC_GetConvertedData(AT91S_ADC *pAdc, unsigned int channel)
{
    unsigned int data=0;
    
    ASSERT(channel < 8, "ADC channel not exist");
    
    switch(channel) {
        case 0: data = pAdc->ADC_CDR0; break;
        case 1: data = pAdc->ADC_CDR1; break;
        case 2: data = pAdc->ADC_CDR2; break;
        case 3: data = pAdc->ADC_CDR3; break;
        #ifdef AT91C_ADC_CDR4
        case 4: data = pAdc->ADC_CDR4; break;
        #endif
        #ifdef AT91C_ADC_CDR5
        case 5: data = pAdc->ADC_CDR5; break;
        #endif
        #ifdef AT91C_ADC_CDR6
        case 6: data = pAdc->ADC_CDR6; break;
        #endif
        #ifdef AT91C_ADC_CDR7
        case 7: data = pAdc->ADC_CDR7; break;    
        #endif
    }
    return data;    
}

//-----------------------------------------------------------------------------
/// Enable ADC interrupt
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \param flag IT to be enabled
//-----------------------------------------------------------------------------
void ADC_EnableIt(AT91S_ADC *pAdc, unsigned int flag)
{
    ASSERT((flag&0xFFF00000)== 0, "ADC bad interrupt IER");

    // Write to the IER register
    if( flag > 0xFFFF ) {
        // General interrupt
        pAdc->ADC_IER = flag;
    }
    else if( flag > 0xFF ) {
        // Overun interrupt
        pAdc->ADC_IER = 1<<flag<<8;
    }
    else {
        // Channel interrupt
        pAdc->ADC_IER = 1<<flag;
    }
}

//-----------------------------------------------------------------------------
/// Enable ADC Data Ready interrupt
/// \param pAdc Pointer to an AT91S_ADC instance.
//-----------------------------------------------------------------------------
void ADC_EnableDataReadyIt(AT91S_ADC *pAdc)
{
    pAdc->ADC_IER = AT91C_ADC_DRDY;
}

//-----------------------------------------------------------------------------
/// Disable ADC interrupt
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \param flag IT to be disabled
//-----------------------------------------------------------------------------
void ADC_DisableIt(AT91S_ADC *pAdc, unsigned int flag)
{
    ASSERT((flag&0xFFF00000)== 0, "ADC bad interrupt IDR");

    // Write to the IDR register
    if( flag > 0xFFFF ) {
        // general interrupt
        pAdc->ADC_IDR = flag;
    }
    else if( flag > 0xFF ) {
        // Overun interrupt
        pAdc->ADC_IDR = 1<<flag<<8;
    }
    else {
        // Channel interrupt
        pAdc->ADC_IDR = 1<<flag;
    }
}

//-----------------------------------------------------------------------------
/// Return ADC Interrupt Status
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \return ADC Stats register
//-----------------------------------------------------------------------------
unsigned int ADC_GetStatus(AT91S_ADC *pAdc)
{
    return pAdc->ADC_SR;
}

//-----------------------------------------------------------------------------
/// Return ADC Interrupt Mask Status
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \return ADC Interrupt Mask Register
//-----------------------------------------------------------------------------
unsigned int ADC_GetInterruptMaskStatus(AT91S_ADC *pAdc)
{
    return pAdc->ADC_IMR;
}

//-----------------------------------------------------------------------------
/// Test if ADC Interrupt is Masked 
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \param flag flag to be tested
/// \return 1 if interrupt is masked, otherwise 0
//-----------------------------------------------------------------------------
unsigned int ADC_IsInterruptMasked(AT91S_ADC *pAdc, unsigned int flag)
{
    return (ADC_GetInterruptMaskStatus(pAdc) & flag);
}

//-----------------------------------------------------------------------------
/// Test if ADC Status is Set
/// \param pAdc Pointer to an AT91S_ADC instance.
/// \param flag flag to be tested
/// \return 1 if the staus is set; 0 otherwise
//-----------------------------------------------------------------------------
unsigned int ADC_IsStatusSet(AT91S_ADC *pAdc, unsigned int flag)
{
    return (ADC_GetStatus(pAdc) & flag);
}


//-----------------------------------------------------------------------------
/// Test if ADC channel interrupt Status is Set
/// \param adc_sr Value of SR register
/// \param channel Channel to be tested
/// \return 1 if interrupt status is set, otherwise 0
//-----------------------------------------------------------------------------
unsigned char ADC_IsChannelInterruptStatusSet(unsigned int adc_sr, 
                                              unsigned int channel)
{
    unsigned char status;
    
    if((adc_sr & (1<<channel)) == (1<<channel)) {
        status = 1;
    }
    else {
        status = 0;
    }
    return status;
}