MHVLib  20111011
An efficiency oriented runtime library for AVR microcontrollers
A:/eclipse/mhvlib/MHV_AD.cpp
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00001 /* Copyright (c) 2011, Make, Hack, Void Inc
00002  * All rights reserved.
00003  *
00004  * Redistribution and use in source and binary forms, with or without
00005  * modification, are permitted provided that the following conditions are met:
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00007  *    notice, this list of conditions and the following disclaimer.
00008  *  * Redistributions in binary form must reproduce the above copyright
00009  *    notice, this list of conditions and the following disclaimer in the
00010  *    documentation and/or other materials provided with the distribution.
00011  *  * Neither the name of the Make, Hack, Void nor the
00012  *    names of its contributors may be used to endorse or promote products
00013  *    derived from this software without specific prior written permission.
00014  *
00015  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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00018  * DISCLAIMED. IN NO EVENT SHALL MAKE, HACK, VOID BE LIABLE FOR ANY
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00023  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00024  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00025  */
00026 
00027 #include "MHV_AD.h"
00028 
00029 uint16_t mhv_ad_busyRead(uint8_t channel, uint8_t reference) {
00030         ADMUX = reference | (channel & 0x0F);
00031 
00032 #ifdef MUX5
00033         ADCSRB = (ADCSRB & ~_BV(MUX5)) | ((channel & _BV(5) >> (5-MUX5)));
00034 #endif
00035 
00036 // Start the conversion
00037         ADCSRA |= _BV(ADSC);
00038 
00039         while (ADCSRA & _BV(ADSC)) {};
00040 
00041         return ADC;
00042 }
00043 
00044 void mhv_ad_asyncRead(uint8_t channel, uint8_t reference) {
00045         ADMUX = reference | (channel & 0x0F);
00046 
00047 #ifdef MUX5
00048         ADCSRB = (ADCSRB & ~_BV(MUX5)) | ((channel & _BV(5) >> (5-MUX5)));
00049 #endif
00050 
00051 // Start the conversion
00052         ADCSRA |= _BV(ADSC);
00053 }
00054 
00055 void mhv_ad_setPrescaler(MHV_AD_PRESCALER prescaler) {
00056         ADCSRA = (ADCSRA & 0xf8) | (prescaler & 0x7);
00057 }