ConfigADC.c

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 *      ***   +++   ***                                                      *
 *      ***   + +   ***                                                      *
 *      ***   +                            CHIPCON CC1010                    *
 *      ***   + +   ***                   HAL - ConfigADC                    *
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 * Author:              ROH                                                  *
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 * Revision history:                                                         *
 *                                                                           *
 * $Log: ConfigADC.c,v $
 * Revision 1.1  2002/10/14 13:04:29  tos
 * Initial version in CVS.
 *
 *                                                                           *
 ****************************************************************************/

#include <chipcon/hal.h>

//----------------------------------------------------------------------------
//  bool halConfigADC(...)
//
//  Description:
//      This function configures the ADC. The _option_ argument is used to
//      select operational mode, _clkFreq_ gives the device clock frequency in 
//      kHz, and _threshold_ is used to set the threshold value for some 
//      operational modes. An interrupt is generated in all modes (except
//      for reset-generating mode in which a reset is generated instead) whenever
//      the 8 MSB of the measured sample is greater or equal to the threshold
//      value. Thus, if an interrupt for each sample is desired, the threshold
//      should be set to 0 (and the ADC and GLOBAL_ADC_DES interrupts enabled.)
//      After configuring the ADC it must be powered up using the ADC_POWER(bool)
//      macro. It should be powered down again when not in use to conserve power.
//      The correct ADC input must be selected using the ADC_SELECT_INPUT(input)
//      macro and started using the ADC_RUN(bool) macro for continuous modes.
//      The ADC_SAMPLE_SINGLE macro is used to initiate a sample acquisition in
//      single-conversion mode, and the ADC_RUNNING macro can be used to
//      determine whether the sample is complete
//      The ADC_GET_SAMPLE_10BIT or ADC_GET_SAMPLE_8BIT macros return the latest
//      sample value.
//
//  Arguments:
//      byte options
//          One or more of the below defined constants define the desired
//          operational mode.
//      word clkFreq
//          The XOSC clock frequency in kHz.
//      byte threshold
//          The threshold value for generating interrupts (and stopping in
//          multi-conversion, stopping mode) or reset (in multi-conversion,
//          reset-generating mode).
//
//  Return value:
//      void
//----------------------------------------------------------------------------
void halConfigADC(byte options, xdata word clkFreq, xdata byte threshold) {
    clkFreq= (clkFreq-250*8)/(250*16);
    ADCON2=(options&0x80)|((byte)clkFreq&0x3F);
    if (options&ADC_INTERRUPT_ENABLE) {
        EXIF&=~0x40;
        ADIE=1;
    }
    ADCON=0x80|(options&0x38);
    ADTRH=threshold;
}    

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