66 lines
1.5 KiB
C
66 lines
1.5 KiB
C
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#ifndef __ADC_ARCH_H__
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#define __ADC_ARCH_H__
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#include <avr/io.h>
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/*
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* Reference voltage
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* The default is 1.6V reference voltage
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* The selected reference voltage is the maximum voltage that can be
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* measured.
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* Directly provide shifted variants so we don't need to shift.
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*/
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#define ADC_1_5 (2<<6)
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#define ADC_1_6 (3<<6)
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#define ADC_1_8 (1<<6)
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#define ADC_EXTERNAL (0<<6)
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#define ADC_DEFAULT ADC_1_6
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/* sometimes it's desirable to decouple setup / finish from sampling */
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static inline void adc_setup (uint8_t ref_volt, uint8_t pin)
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{
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ADMUX = ref_volt | (pin & 0x7);
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ADCSRA = _BV(ADEN) | _BV(ADPS0) | _BV(ADPS2);
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}
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static inline int adc_read (void)
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{
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ADCSRA |= (1 << ADSC);
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loop_until_bit_is_clear (ADCSRA, ADSC);
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return ADC;
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}
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static inline void adc_fin (void)
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{
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ADCSRA = 0;
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ADMUX = 0;
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}
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static inline void adc_init (void)
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{
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uint8_t temp;
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ADCSRC = 0;
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ADCSRB = 0;
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adc_fin ();
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/*
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* Disable JTAG interface
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* Hardware manual about JTD bit:
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* "In order to avoid unintentional disabling or enabling of the
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* JTAG interface, a timed sequence must be followed when changing
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* this bit: The application software must write this bit to the
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* desired value twice within four cycles to change its value."
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* 15.4.1 "MCUCR - MCU Control Register", p. 219
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*/
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temp = MCUCR | (1 << JTD);
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MCUCR = temp;
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MCUCR = temp;
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}
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int readADC(uint8_t pin);
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long readVcc();
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int readInternalTemp(void);
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void analogReference(uint8_t mode);
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#endif /* __ADC_ARCH_H__ */
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