ADC configuration and service functions. More...

#include <stddef.h>
#include <avr/interrupt.h>
#include <avr/pgmspace.h>
#include "adc.h"
#include "math.h"
#include "midi.h"
#include "leds.h"
#include "usb.h"

Include dependency graph for adc.c:

Data Structures
struct	adc_channel_regs
	ADC channel configuration registers. More...

Functions
static uint16_t	compensate_offset (uint16_t sample)

static uint16_t	perform_filtered_measurement (enum adc_channel channel)

uint16_t	calibrate_adc_offset (enum adc_channel channel)
	Calibrates the ADC offset using the given channel. More...

void	disable_adc_interrupt (enum adc_channel channel)
	Disables the interrupt for an ADC channel. More...

void	enable_adc_interrupt (enum adc_channel channel)
	Enables the interrupt for an ADC channel. More...

void	init_adc_module (const struct adc_config *const config)
	Initializes and calibrates the ADC. More...

void	init_adc_conversion (const struct adc_conversion_config *const config)
	Sets up an ADC conversion. More...

void	set_adc_channel0_max_value (void)
	Defines the current ADC value as MIDI max value. More...

void	set_adc_channel0_min_value (void)
	Defines the current ADC value as MIDI min value. More...

void	set_adc_offset (uint16_t new_offset)
	Sets the ADC offset. More...

void	trigger_adc (enum adc_channel channel)
	Triggers a conversion for the given channel. More...

	ISR (ADCA_CH0_vect)
	Interrupt service routine for ADC channel 0. More...

static void	invoke_callbacks (enum adc_channel channel, uint16_t value)
	Invokes registered callbacks for the given channels. More...

	ISR (ADCA_CH1_vect)
	Interrupt service routine for ADC channel 1. More...

	ISR (ADCA_CH2_vect)
	Interrupt service routine for ADC channel 2. More...

	ISR (ADCA_CH3_vect)
	Interrupt service routine for ADC channel 3. More...

Variables
static const struct adc_channel_regs	adc_regs []
	Lookup table for ADC channel configuration registers. More...

static uint16_t	offset
	ADC offset. More...

static uint16_t	sample_buffer [(1<<(8 *sizeof(adc_accumulator) - 12))]
	Buffer for ADC conversion results of channel 0. More...

static void(*	callbacks_signed [sizeof(adc_regs)/sizeof(struct adc_channel_regs)])(int16_t)
	Conversion callbacks for signed values. More...

static void(*	callbacks_unsigned [sizeof(adc_regs)/sizeof(struct adc_channel_regs)])(uint16_t)
	Conversion callbacks for unsigned values. More...

static struct linear_range *	adc_input_range
	Conversion callbacks for unsigned values. More...

Detailed Description

ADC configuration and service functions.

Function Documentation

◆ calibrate_adc_offset()

uint16_t calibrate_adc_offset ( enum adc_channel channel )

Calibrates the ADC offset using the given channel.

Parameters

channel the ADC channel

Returns: the measured offset

◆ compensate_offset()

static uint16_t compensate_offset ( uint16_t sample )

static

◆ disable_adc_interrupt()

void disable_adc_interrupt ( enum adc_channel channel )

inline

Disables the interrupt for an ADC channel.

Parameters

channel the ADC channel

◆ enable_adc_interrupt()

void enable_adc_interrupt ( enum adc_channel channel )

inline

Enables the interrupt for an ADC channel.

Parameters

channel the ADC channel

◆ init_adc_conversion()

void init_adc_conversion ( const struct adc_conversion_config * config )

Sets up an ADC conversion.

Registers the callbacks, configures the input and performs a dummy-conversion. The GPIO pin is not configured here – this must be done through the GPIO module.

Parameters

config the ADC conversion configuration

See also: init_gpio_module

◆ init_adc_module()

void init_adc_module ( const struct adc_config * config )

Initializes and calibrates the ADC.

Selects the voltage reference, sets the clock prescaler and conversion mode and calibrates the ADC

Parameters

config the shared ADC configuration

◆ invoke_callbacks()

static void invoke_callbacks	(	enum adc_channel	channel,
		uint16_t	value
	)

static

Invokes registered callbacks for the given channels.

Parameters

channel	the ADC channel whose callbacks should be invoked
value	the ADC conversion result

◆ ISR() [1/4]

ISR ( ADCA_CH0_vect )

Interrupt service routine for ADC channel 0.

This routine is different from the others: It computes a mean value of the last ADC_SAMPLE_BUFFER_SIZE samples, converts the result to a valid MIDI value in the range [0, 127] and passes it to the callback for unsigned values. All this happens in an atomic block.

◆ ISR() [2/4]

ISR ( ADCA_CH1_vect )

Interrupt service routine for ADC channel 1.

Calls the registered callback(s) for the channel in an atomic block.

◆ ISR() [3/4]

ISR ( ADCA_CH2_vect )

Interrupt service routine for ADC channel 2.

Calls the registered callback(s) for the channel in an atomic block.

◆ ISR() [4/4]

ISR ( ADCA_CH3_vect )

Interrupt service routine for ADC channel 3.

Calls the registered callback(s) for the channel in an atomic block.

◆ perform_filtered_measurement()

static uint16_t perform_filtered_measurement ( enum adc_channel channel )

static

◆ set_adc_channel0_max_value()

void set_adc_channel0_max_value ( void )

Defines the current ADC value as MIDI max value.

◆ set_adc_channel0_min_value()

void set_adc_channel0_min_value ( void )

Defines the current ADC value as MIDI min value.

◆ set_adc_offset()

void set_adc_offset ( uint16_t offset )

Sets the ADC offset.

Parameters

offset the offset

◆ trigger_adc()

void trigger_adc ( enum adc_channel channel )

Triggers a conversion for the given channel.

Parameters

channel the ADC channel

Variable Documentation

◆ adc_input_range

struct linear_range* adc_input_range

static

Conversion callbacks for unsigned values.

Used in the interrupt service routines

◆ adc_regs

const struct adc_channel_regs adc_regs[]

static

Initial value:

= {
    { 
        .control_register   = &ADCA_CH0_CTRL,
        .mux_register       = &ADCA_CH0_MUXCTRL,
        .interrupt_register = &ADCA_CH0_INTCTRL,
        .interrupt_flag     = &ADCA_CH0_INTFLAGS,
        .result_register    = &ADCA.CH0RES
    },
    { 
        .control_register   = &ADCA_CH1_CTRL,
        .mux_register       = &ADCA_CH1_MUXCTRL,
        .interrupt_register = &ADCA_CH1_INTCTRL,
        .interrupt_flag     = &ADCA_CH1_INTFLAGS,
        .result_register    = &ADCA.CH1RES
    },
    { 
        .control_register   = &ADCA_CH2_CTRL,
        .mux_register       = &ADCA_CH2_MUXCTRL,
        .interrupt_register = &ADCA_CH2_INTCTRL,
        .interrupt_flag     = &ADCA_CH2_INTFLAGS,
        .result_register    = &ADCA.CH2RES
    },
    { 
        .control_register   = &ADCA_CH3_CTRL,
        .mux_register       = &ADCA_CH3_MUXCTRL,
        .interrupt_register = &ADCA_CH3_INTCTRL,
        .interrupt_flag     = &ADCA_CH3_INTFLAGS,
        .result_register    = &ADCA.CH3RES
    },
}

Lookup table for ADC channel configuration registers.

◆ callbacks_signed

void(* callbacks_signed[sizeof(adc_regs)/sizeof(struct adc_channel_regs)])(int16_t)

static

Conversion callbacks for signed values.

Used in the interrupt service routines

◆ callbacks_unsigned

void(* callbacks_unsigned[sizeof(adc_regs)/sizeof(struct adc_channel_regs)])(uint16_t)

static

Conversion callbacks for unsigned values.

Used in the interrupt service routines

◆ offset

uint16_t offset

static

ADC offset.

Set during offset calibration

◆ sample_buffer

uint16_t sample_buffer[(1<<(8 *sizeof(adc_accumulator) - 12))]

static

Buffer for ADC conversion results of channel 0.

See also: ISR(ADCA_CH0_vect)

Data Structures

Functions

Variables

Detailed Description

Function Documentation

◆ calibrate_adc_offset()

◆ compensate_offset()

◆ disable_adc_interrupt()

◆ enable_adc_interrupt()

◆ init_adc_conversion()

◆ init_adc_module()

◆ invoke_callbacks()

◆ ISR() [1/4]

◆ ISR() [2/4]

◆ ISR() [3/4]

◆ ISR() [4/4]

◆ perform_filtered_measurement()

◆ set_adc_channel0_max_value()

◆ set_adc_channel0_min_value()

◆ set_adc_offset()

◆ trigger_adc()

Variable Documentation

◆ adc_input_range

◆ adc_regs

◆ callbacks_signed

◆ callbacks_unsigned

◆ offset

◆ sample_buffer