mirror of
https://github.com/stargieg/bacnet-stack
synced 2025-10-26 23:35:52 +08:00
132 lines
4.3 KiB
C
132 lines
4.3 KiB
C
/**************************************************************************
|
|
*
|
|
* Copyright (C) 2009 Steve Karg <skarg@users.sourceforge.net>
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining
|
|
* a copy of this software and associated documentation files (the
|
|
* "Software"), to deal in the Software without restriction, including
|
|
* without limitation the rights to use, copy, modify, merge, publish,
|
|
* distribute, sublicense, and/or sell copies of the Software, and to
|
|
* permit persons to whom the Software is furnished to do so, subject to
|
|
* the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included
|
|
* in all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
|
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
|
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
|
|
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
|
|
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
|
|
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
|
|
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
|
*********************************************************************/
|
|
#include <stdbool.h>
|
|
#include <stdint.h>
|
|
#include "hardware.h"
|
|
/* me */
|
|
#include "adc.h"
|
|
|
|
/* prescale select bits */
|
|
#if (F_CPU >> 1) < 1000000
|
|
#define ADPS_8BIT (1)
|
|
#define ADPS_10BIT (3)
|
|
#elif (F_CPU >> 2) < 1000000
|
|
#define ADPS_8BIT (2)
|
|
#define ADPS_10BIT (4)
|
|
#elif (F_CPU >> 3) < 1000000
|
|
#define ADPS_8BIT (3)
|
|
#define ADPS_10BIT (5)
|
|
#elif (F_CPU >> 4) < 1000000
|
|
#define ADPS_8BIT (4)
|
|
#define ADPS_10BIT (6)
|
|
#elif (F_CPU >> 5) < 1000000
|
|
#define ADPS_8BIT (5)
|
|
#define ADPS_10BIT (7)
|
|
#else
|
|
#error "ADC: F_CPU too large for accuracy."
|
|
#endif
|
|
|
|
/* ADMUX: channel bits 0..4
|
|
ADLAR = Left Adjust Result
|
|
REFSx = hardware setup: cap on AREF
|
|
*/
|
|
/* ADCSRA:
|
|
ADEN = Enable
|
|
ADSC = Start conversion
|
|
ADIF = Interrupt Flag
|
|
ADIE = Interrupt Enable
|
|
ADATE = Auto Trigger Enable
|
|
*/
|
|
|
|
void adc_enable(
|
|
uint8_t index)
|
|
{
|
|
index = index;
|
|
/* do nothing */
|
|
}
|
|
|
|
/**************************************************
|
|
* Description: Run a Analog to Digital conversion
|
|
* Returns: none
|
|
* Notes: none
|
|
**************************************************/
|
|
uint8_t adc_result_8bit(
|
|
uint8_t channel)
|
|
{ /* 0..7 = ADC0..ADC7, respectively */
|
|
uint8_t value = 0; /* return value */
|
|
|
|
while (ADCSRA & (1 << ADSC));
|
|
ADMUX = channel | (1 << ADLAR) | (0 << REFS1) | (1 << REFS0);
|
|
/* Delay needed for the stabilization of the ADC input voltage */
|
|
_delay_us(10);
|
|
/* Start the analog to digital conversion */
|
|
ADCSRA = (1 << ADEN) | (1 << ADSC) | (1 << ADIF) | ADPS_8BIT;
|
|
/* Wait for the analog to digital conversion to complete */
|
|
while ((ADCSRA & (1 << ADIF)) == 0);
|
|
value = ADCH;
|
|
|
|
return value;
|
|
}
|
|
|
|
/**************************************************
|
|
* Description: Run a Analog to Digital conversion
|
|
* Returns: none
|
|
* Notes: none
|
|
**************************************************/
|
|
uint16_t adc_result_10bit(
|
|
uint8_t channel)
|
|
{ /* 0..7 = ADC0..ADC7, respectively */
|
|
uint16_t value = 0; /* return value */
|
|
|
|
while (ADCSRA & (1 << ADSC));
|
|
ADMUX = channel | (0 << ADLAR) | (0 << REFS1) | (1 << REFS0);
|
|
/* Delay needed for the stabilization of the ADC input voltage */
|
|
_delay_us(10);
|
|
/* Start the analog to digital conversion */
|
|
ADCSRA = (1 << ADEN) | (1 << ADSC) | (1 << ADIF) | ADPS_10BIT;
|
|
/* Wait for the analog to digital conversion to complete */
|
|
while ((ADCSRA & (1 << ADIF)) == 0);
|
|
value = ADCL;
|
|
value |= (ADCH << 8);
|
|
|
|
return value;
|
|
}
|
|
|
|
/**************************************************
|
|
* Description: Initializes the Analog to Digital Converter
|
|
* Returns: none
|
|
* Notes: none
|
|
**************************************************/
|
|
void adc_init(
|
|
void)
|
|
{
|
|
/* configure ADC for Free Running Mode - ADTS = 000 */
|
|
/* AIN1 is applied to the negative input of the Analog Comparator - ACME */
|
|
BITMASK_CLEAR(ADCSRB, _BV(ACME) | _BV(ADTS2) | _BV(ADTS1) | _BV(ADTS0));
|
|
/* Digital input not needed on ADC0, so disable it to save power */
|
|
BIT_SET(DIDR0, ADC0D);
|
|
/* Clear the Power Reduction bit to enable ADC */
|
|
BIT_CLEAR(PRR, PRADC);
|
|
}
|