Kari Argillander
cb243c36a8
* Change MIT license texts to SPDX-License-Identifier SPDX-License-Identifier is much easier to understand and grep than license text so use that instead. * Change GPL exception license texts to SPDX-License-Identifier SPDX-License-Identifier is much easier to understand and grep than license text so use that instead. * Change misc license texts to SPDX-License-Identifier There are some external code in repo which are not licenses as most of the stuff in this repo. We still want every file to have SPDX identifier to easily grep licenses. * Add currently used license files Even though Bacnet-Stack is using SPDX identifiers we still need to give those license files with source. For this reason add all license files to license/ folder. SPDX has also files which would make same thing but this is style which example Linux kernel is using and it is quite clear so I choose that one for now. I choosed not yet bring CC-PDDC as that is not right license for those files. --------- Co-authored-by: Kari Argillander <kari.argillander@fidelix.com>
116 lines
3.3 KiB
C
116 lines
3.3 KiB
C
/**************************************************************************
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*
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* Copyright (C) 2009 Steve Karg <skarg@users.sourceforge.net>
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*
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* SPDX-License-Identifier: MIT
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*
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*********************************************************************/
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#include <stdbool.h>
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#include <stdint.h>
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#include "hardware.h"
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/* me */
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#include "adc.h"
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/* prescale select bits */
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#if (F_CPU >> 1) < 1000000
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#define ADPS_8BIT (1)
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#define ADPS_10BIT (3)
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#elif (F_CPU >> 2) < 1000000
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#define ADPS_8BIT (2)
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#define ADPS_10BIT (4)
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#elif (F_CPU >> 3) < 1000000
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#define ADPS_8BIT (3)
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#define ADPS_10BIT (5)
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#elif (F_CPU >> 4) < 1000000
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#define ADPS_8BIT (4)
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#define ADPS_10BIT (6)
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#elif (F_CPU >> 5) < 1000000
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#define ADPS_8BIT (5)
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#define ADPS_10BIT (7)
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#else
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#error "ADC: F_CPU too large for accuracy."
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#endif
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/* ADMUX: channel bits 0..4
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ADLAR = Left Adjust Result
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REFSx = hardware setup: cap on AREF
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*/
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/* ADCSRA:
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ADEN = Enable
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ADSC = Start conversion
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ADIF = Interrupt Flag
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ADIE = Interrupt Enable
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ADATE = Auto Trigger Enable
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*/
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void adc_enable(uint8_t index)
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{
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index = index;
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/* do nothing */
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}
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/**************************************************
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* Description: Run a Analog to Digital conversion
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* Returns: none
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* Notes: none
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**************************************************/
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uint8_t adc_result_8bit(uint8_t channel)
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{ /* 0..7 = ADC0..ADC7, respectively */
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uint8_t value = 0; /* return value */
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while (ADCSRA & (1 << ADSC))
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;
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ADMUX = channel | (1 << ADLAR) | (0 << REFS1) | (1 << REFS0);
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/* Delay needed for the stabilization of the ADC input voltage */
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_delay_us(10);
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/* Start the analog to digital conversion */
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ADCSRA = (1 << ADEN) | (1 << ADSC) | (1 << ADIF) | ADPS_8BIT;
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/* Wait for the analog to digital conversion to complete */
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while ((ADCSRA & (1 << ADIF)) == 0)
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;
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value = ADCH;
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return value;
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}
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/**************************************************
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* Description: Run a Analog to Digital conversion
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* Returns: none
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* Notes: none
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**************************************************/
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uint16_t adc_result_10bit(uint8_t channel)
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{ /* 0..7 = ADC0..ADC7, respectively */
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uint16_t value = 0; /* return value */
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while (ADCSRA & (1 << ADSC))
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;
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ADMUX = channel | (0 << ADLAR) | (0 << REFS1) | (1 << REFS0);
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/* Delay needed for the stabilization of the ADC input voltage */
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_delay_us(10);
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/* Start the analog to digital conversion */
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ADCSRA = (1 << ADEN) | (1 << ADSC) | (1 << ADIF) | ADPS_10BIT;
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/* Wait for the analog to digital conversion to complete */
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while ((ADCSRA & (1 << ADIF)) == 0)
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;
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value = ADCL;
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value |= (ADCH << 8);
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return value;
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}
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/**************************************************
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* Description: Initializes the Analog to Digital Converter
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* Returns: none
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* Notes: none
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**************************************************/
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void adc_init(void)
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{
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/* configure ADC for Free Running Mode - ADTS = 000 */
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/* AIN1 is applied to the negative input of the Analog Comparator - ACME */
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BITMASK_CLEAR(ADCSRB, _BV(ACME) | _BV(ADTS2) | _BV(ADTS1) | _BV(ADTS0));
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/* Digital input not needed on ADC0, so disable it to save power */
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BIT_SET(DIDR0, ADC0D);
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/* Clear the Power Reduction bit to enable ADC */
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BIT_CLEAR(PRR, PRADC);
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}
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