SAM4L Analog Comparator Interface Controller (ACIFC) Driver

This driver for Atmel® | SMART ARM®-based microcontrollers provides an interface for the configuration and management of the device's Analog Comparator Interface Controller functionality.

The Analog Comparator Interface controls eight Analog Comparators (AC) with identical behavior. Each Analog Comparator compares two voltages, yielding an output that depends on the result of the comparison.

Devices from the following series can use this module:

• Atmel | SMART SAM4L

The outline of this documentation is as follows:

• Prerequisites
• Module Overview
• Special Considerations
• Extra Information
• Examples
• API Overview

Prerequisites

There are no prerequisites for this module.

Module Overview

The Analog Comparator Interface (ACIFC) controls a number of Analog Comparators (AC) with identical behavior. Each Analog Comparator compares two voltages and gives a compare output depending on the results of this comparison.

The ACIFC module can be configured in normal mode, in which each comparator is used independently, or in window mode, which uses defined comparator pairs. The comparators do not all have to be in the same mode; some comparators may be in normal mode, while others are in window mode. There are, however, restrictions on which ACs can be grouped together in window mode.

Special Considerations

I/O Lines

The ACIFC pins are multiplexed with other peripherals. The user application must therefore configure the GPIO Controller, to give the ACIFC module control of the associated pins.

Power Management

The ACIFC stops functioning when the system enters a sleep mode that disables its clock. However, the ACIFC module can resume its operation if the system enters the SleepWalking mode and the ACIFC clock is started by the Peripheral Event System. During this time, if the ACIFC module generates an interrupt, the system will wake-up from sleep mode and normal system operation resumes.

Clocks

The clock for ACIFC (CLK_ACIFC) is generated by the Power Manager (PM). It can be manually disabled, through the Power Manager, or may be automatically disabled when the system enters a sleep mode that disables the clocks to the peripheral bus modules.

Interrupts

The ACIFC interrupt request line is connected to the Nested Vectored Interrupt Controller (NVIC). Using the ACIFC interrupt requires that the NVIC be configured beforehand.

Peripheral Events

The ACIFC peripheral events are connected via the Peripheral Event System.

Debug Operation

When an external debugger forces the CPU into debug mode, the ACIFC module continues normal operation. If the ACIFC module is configured in a way that requires it to be periodically serviced by the CPU through interrupts (or similar), debugging may result in improper operation or data loss.

Extra Information

For extra information, see Extra Information for Analog Comparator Interface Driver. This includes:

• Acronyms
• Dependencies
• Errata
• Module History

Examples

For a list of examples related to this driver, see Examples for Analog Comparator Interface.

API Overview

Data Structures
struct	ac_ch_config
	ACIFC channel configuration structure. More...
struct	ac_config
	ACIFC module configuration structure. More...
struct	ac_dev_inst
	ACIFC driver structure. More...
struct	ac_win_config
	ACIFC window configuration structure. More...

Typedefs
typedef void(*	ac_callback_t )(void)
	ACIFC interrupt callback type. More...
typedef enum ac_interrupt_source	ac_interrupt_source_t
	ACIFC interrupt configuration type. More...

Enumerations
enum	ac_ch_interrupt_setting {   AC_CH_IS_VINP_GT_VINN = 0,   AC_CH_IS_VINP_LT_VINN,   AC_CH_IS_OUTPUT_TGL,   AC_CH_IS_COMP_DONE }
	ACIFC channel interrupt setting. More...
enum	ac_comparator_mode {   AC_COMPARATOR_OFF = 0,   AC_COMPARATOR_CONTINUOUS,   AC_COMPARATOR_USER_TRIGGERED,   AC_COMPARATOR_EVENT_TRIGGERED }
	ACIFC comparator mode. More...
enum	ac_hysteresis_voltage {   AC_HYSTERESIS_0_MV = 0,   AC_HYSTERESIS_25_MV,   AC_HYSTERESIS_50_MV,   AC_HYSTERESIS_75_MV }
	ACIFC hysteresis voltage. More...
enum	ac_interrupt_source {   AC_INTERRUPT_CONVERSION_COMPLETED_0 = 0,   AC_INTERRUPT_STARTUP_TIME_ELAPSED_0,   AC_INTERRUPT_CONVERSION_COMPLETED_1,   AC_INTERRUPT_STARTUP_TIME_ELAPSED_1,   AC_INTERRUPT_CONVERSION_COMPLETED_2,   AC_INTERRUPT_STARTUP_TIME_ELAPSED_2,   AC_INTERRUPT_CONVERSION_COMPLETED_3,   AC_INTERRUPT_STARTUP_TIME_ELAPSED_3,   AC_INTERRUPT_CONVERSION_COMPLETED_4,   AC_INTERRUPT_STARTUP_TIME_ELAPSED_4,   AC_INTERRUPT_CONVERSION_COMPLETED_5,   AC_INTERRUPT_STARTUP_TIME_ELAPSED_5,   AC_INTERRUPT_CONVERSION_COMPLETED_6,   AC_INTERRUPT_STARTUP_TIME_ELAPSED_6,   AC_INTERRUPT_CONVERSION_COMPLETED_7,   AC_INTERRUPT_STARTUP_TIME_ELAPSED_7,   AC_INTERRUPT_WINDOW_0,   AC_INTERRUPT_WINDOW_1,   AC_INTERRUPT_WINDOW_2,   AC_INTERRUPT_WINDOW_3 }
	ACIFC interrupt configuration type. More...
enum	ac_negative_input { AC_NEGTIVE_INPUT_EXTERNAL = 0 }
	ACIFC negative input. More...
enum	ac_win_event_source {   AC_WIN_EVENT_ACWOUT_RISING_EDGE = 0,   AC_WIN_EVENT_ACWOUT_FALLING_EDGE,   AC_WIN_EVENT_ACWOUT_ON_ANY_EDGE,   AC_WIN_EVENT_INSIDE_WINDOW,   AC_WIN_EVENT_OUTSIDE_WINDOW,   AC_WIN_EVENT_MEASURE_DONE }
	ACIFC window event output configuration. More...
enum	ac_win_interrupt_setting {   AC_WIN_IS_VINP_INSIDE_WINDOW = 0,   AC_WIN_IS_VINP_OUTSIDE_WINDOW,   AC_WIN_IS_WINDOW_OUTPUT_TGL,   AC_WIN_IS_WINDOW_COMP_DONE,   AC_WIN_IS_VINP_ENTER_WINDOW,   AC_WIN_IS_VINP_LEAVE_WINDOW }
	ACIFC window interrupt settings. More...

Functions
static void	ac_ch_get_config_defaults (struct ac_ch_config *const cfg)
	Initializes an ACIFC channel configuration structure to default values. More...
void	ac_ch_set_config (struct ac_dev_inst *const dev_inst, uint32_t channel, struct ac_ch_config *cfg)
	Configure the specified ACIFC channel. More...
static void	ac_clear_interrupt_status (struct ac_dev_inst *const dev_inst, uint32_t status)
	Write to the ACIFC interrupt status. More...
void	ac_disable (struct ac_dev_inst *const dev_inst)
	Disable the ACIFC Module. More...
void	ac_disable_interrupt (struct ac_dev_inst *const dev_inst, ac_interrupt_source_t source)
	Disable the specified ACIFC interrupt source. More...
void	ac_enable (struct ac_dev_inst *const dev_inst)
	Enable the ACIFC module. More...
void	ac_enable_interrupt (struct ac_dev_inst *const dev_inst, ac_interrupt_source_t source)
	Enable the specified ACIFC interrupt source. More...
static void	ac_get_config_defaults (struct ac_config *const cfg)
	Initialize an ACIFC configuration structure to default values. More...
static uint32_t	ac_get_interrupt_mask (struct ac_dev_inst *const dev_inst)
	Get the ACIFC interrupt mask. More...
static uint32_t	ac_get_interrupt_status (struct ac_dev_inst *const dev_inst)
	Get the ACIFC interrupt status. More...
static uint32_t	ac_get_status (struct ac_dev_inst *const dev_inst)
	Get the ACIFC status. More...
enum status_code	ac_init (struct ac_dev_inst *const dev_inst, Acifc *const ac, struct ac_config *const cfg)
	Initialize the ACIFC module. More...
static bool	ac_is_comparison_done (struct ac_dev_inst *const dev_inst)
	Check if the ACIFC comparison is done. More...
void	ac_set_callback (struct ac_dev_inst *const dev_inst, ac_interrupt_source_t source, ac_callback_t callback, uint8_t irq_level)
	Set the ACIFC interrupt callback. More...
static void	ac_user_trigger_single_comparison (struct ac_dev_inst *const dev_inst)
	Start a single ACIFC comparison. More...
static void	ac_win_get_config_defaults (struct ac_win_config *const cfg)
	Initializes an ACIFC window configuration structure to default values. More...
void	ac_win_set_config (struct ac_dev_inst *const dev_inst, uint32_t window, struct ac_win_config *cfg)
	Configure the specified ACIFC window. More...

typedef void(* ac_callback_t)(void)

ACIFC interrupt callback type.

typedef enum ac_interrupt_source ac_interrupt_source_t

ACIFC interrupt configuration type.

enum ac_ch_interrupt_setting

ACIFC channel interrupt setting.

Enumerator
AC_CH_IS_VINP_GT_VINN	Interrupt when VINP > VINN
AC_CH_IS_VINP_LT_VINN	Interrupt when VINP < VINN
AC_CH_IS_OUTPUT_TGL	Interrupt on toggle of ACOUT.
AC_CH_IS_COMP_DONE	Interrupt when comparison of VINP and VINN is done.

enum ac_comparator_mode

ACIFC comparator mode.

Enumerator
AC_COMPARATOR_OFF	Off.
AC_COMPARATOR_CONTINUOUS	Continuous measurement mode.
AC_COMPARATOR_USER_TRIGGERED	User triggered single measurement mode.
AC_COMPARATOR_EVENT_TRIGGERED	Peripheral event triggered single measurement mode.

enum ac_hysteresis_voltage

ACIFC hysteresis voltage.

Enumerator
AC_HYSTERESIS_0_MV	0mV of hysteresis
AC_HYSTERESIS_25_MV	25mV of hysteresis
AC_HYSTERESIS_50_MV	50mV of hysteresis
AC_HYSTERESIS_75_MV	75mV of hysteresis

enum ac_interrupt_source

ACIFC interrupt configuration type.

Enumerator
AC_INTERRUPT_CONVERSION_COMPLETED_0	Conversion completed on channel 0.
AC_INTERRUPT_STARTUP_TIME_ELAPSED_0	Start-up time elapsed on channel 0.
AC_INTERRUPT_CONVERSION_COMPLETED_1	Conversion completed on channel 1.
AC_INTERRUPT_STARTUP_TIME_ELAPSED_1	Start-up time elapsed on channel 1.
AC_INTERRUPT_CONVERSION_COMPLETED_2	Conversion completed on channel 2.
AC_INTERRUPT_STARTUP_TIME_ELAPSED_2	Start-up time elapsed on channel 2.
AC_INTERRUPT_CONVERSION_COMPLETED_3	Conversion completed on channel 3.
AC_INTERRUPT_STARTUP_TIME_ELAPSED_3	Start-up time elapsed on channel 3.
AC_INTERRUPT_CONVERSION_COMPLETED_4	Conversion completed on channel 4.
AC_INTERRUPT_STARTUP_TIME_ELAPSED_4	Start-up time elapsed on channel 4.
AC_INTERRUPT_CONVERSION_COMPLETED_5	Conversion completed on channel 5.
AC_INTERRUPT_STARTUP_TIME_ELAPSED_5	Start-up time elapsed on channel 5.
AC_INTERRUPT_CONVERSION_COMPLETED_6	Conversion completed on channel 6.
AC_INTERRUPT_STARTUP_TIME_ELAPSED_6	Start-up time elapsed on channel 6.
AC_INTERRUPT_CONVERSION_COMPLETED_7	Conversion completed on channel 7.
AC_INTERRUPT_STARTUP_TIME_ELAPSED_7	Start-up time elapsed on channel 7.
AC_INTERRUPT_WINDOW_0	Window 0 interrupt.
AC_INTERRUPT_WINDOW_1	Window 1 interrupt.
AC_INTERRUPT_WINDOW_2	Window 2 interrupt.
AC_INTERRUPT_WINDOW_3	Window 3 interrupt.

enum ac_negative_input

ACIFC negative input.

Enumerator
AC_NEGTIVE_INPUT_EXTERNAL	ACANx (ACBNx) pin selected.

enum ac_win_event_source

ACIFC window event output configuration.

Enumerator
AC_WIN_EVENT_ACWOUT_RISING_EDGE	ACWOUT rising edge.
AC_WIN_EVENT_ACWOUT_FALLING_EDGE	ACWOUT falling edge.
AC_WIN_EVENT_ACWOUT_ON_ANY_EDGE	ACWOUT rising or falling edge.
AC_WIN_EVENT_INSIDE_WINDOW	Inside window.
AC_WIN_EVENT_OUTSIDE_WINDOW	Outside window.
AC_WIN_EVENT_MEASURE_DONE	Measurement done.

enum ac_win_interrupt_setting

ACIFC window interrupt settings.

Enumerator
AC_WIN_IS_VINP_INSIDE_WINDOW	Window interrupt as soon as the common input voltage is inside the window.
AC_WIN_IS_VINP_OUTSIDE_WINDOW	Window interrupt as soon as the common input voltage is outside the window.
AC_WIN_IS_WINDOW_OUTPUT_TGL	Window interrupt on toggle of ACWOUT.
AC_WIN_IS_WINDOW_COMP_DONE	Window interrupt when evaluation of common input voltage is done.
AC_WIN_IS_VINP_ENTER_WINDOW	Window interrupt when the common input voltage enters the window (e.g. the rising-edge of ACWOUT)
AC_WIN_IS_VINP_LEAVE_WINDOW	Window interrupt when the common input voltage leaves the window (e.g. the falling-edge of ACWOUT)

static void ac_ch_get_config_defaults ( struct ac_ch_config *const  cfg )

inlinestatic

Initializes an ACIFC channel configuration structure to default values.

Note

This function should be called to prepare all new instances of ACIFC channel configuration structures before they are further modified by the user application.

The default configuration is as follows:

• Hysteresis voltage = 0mV
• ACIFC is disabled between measurements
• Fast mode is disabled
• No output peripheral event when ACOUT is zero or one
• Negative input from the external pin
• User triggered single measurement mode
• Interrupt enabled when the comparison is done

Parameters

[out]

cfg

ACIFC channel configuration structure pointer

References AC_CH_IS_COMP_DONE, AC_COMPARATOR_USER_TRIGGERED, AC_HYSTERESIS_0_MV, AC_NEGTIVE_INPUT_EXTERNAL, ac_ch_config::always_on, Assert, ac_ch_config::comparator_mode, ac_ch_config::event_negative, ac_ch_config::event_positive, ac_ch_config::fast_mode, ac_ch_config::hysteresis_voltage, ac_ch_config::interrupt_setting, and ac_ch_config::negative_input.

Referenced by run_ac_test().

void ac_ch_set_config	(	struct ac_dev_inst *const	dev_inst,
		uint32_t	channel,
		struct ac_ch_config *	cfg
	)

Configure the specified ACIFC channel.

Parameters

[in]	dev_inst	Driver structure pointer
[in]	channel	ACIFC channel number (range 0 to 7 inclusive)
[in]	cfg	ACIFC channel configuration structure pointer

References ac_ch_config::always_on, Assert, ac_ch_config::comparator_mode, ac_ch_config::event_negative, ac_ch_config::event_positive, ac_ch_config::fast_mode, ac_dev_inst::hw_dev, ac_ch_config::hysteresis_voltage, ac_ch_config::interrupt_setting, and ac_ch_config::negative_input.

Referenced by run_ac_test().

static void ac_clear_interrupt_status ( struct ac_dev_inst *const  dev_inst, uint32_t  status  )

inlinestatic

Write to the ACIFC interrupt status.

Parameters

[in]	dev_inst	Driver structure pointer
[in]	status	Interrupt status to be clear

References ac_dev_inst::hw_dev.

Referenced by set_int_flag().

void ac_disable

(

struct ac_dev_inst *const

dev_inst

)

Disable the ACIFC Module.

Parameters

[in]

dev_inst

Driver structure pointer

References ac_dev_inst::hw_dev, SLEEPMGR_BACKUP, and sleepmgr_unlock_mode().

void ac_disable_interrupt	(	struct ac_dev_inst *const	dev_inst,
		ac_interrupt_source_t	source
	)

Disable the specified ACIFC interrupt source.

Parameters

[in]	dev_inst	Driver structure pointer
[in]	source	Interrupt source to disable

References AC_INTERRUPT_CONVERSION_COMPLETED_0, AC_INTERRUPT_CONVERSION_COMPLETED_1, AC_INTERRUPT_CONVERSION_COMPLETED_2, AC_INTERRUPT_CONVERSION_COMPLETED_3, AC_INTERRUPT_CONVERSION_COMPLETED_4, AC_INTERRUPT_CONVERSION_COMPLETED_5, AC_INTERRUPT_CONVERSION_COMPLETED_6, AC_INTERRUPT_CONVERSION_COMPLETED_7, AC_INTERRUPT_STARTUP_TIME_ELAPSED_0, AC_INTERRUPT_STARTUP_TIME_ELAPSED_1, AC_INTERRUPT_STARTUP_TIME_ELAPSED_2, AC_INTERRUPT_STARTUP_TIME_ELAPSED_3, AC_INTERRUPT_STARTUP_TIME_ELAPSED_4, AC_INTERRUPT_STARTUP_TIME_ELAPSED_5, AC_INTERRUPT_STARTUP_TIME_ELAPSED_6, AC_INTERRUPT_STARTUP_TIME_ELAPSED_7, AC_INTERRUPT_WINDOW_0, AC_INTERRUPT_WINDOW_1, AC_INTERRUPT_WINDOW_2, AC_INTERRUPT_WINDOW_3, Assert, and ac_dev_inst::hw_dev.

void ac_enable

(

struct ac_dev_inst *const

dev_inst

)

Enable the ACIFC module.

Parameters

[in]

dev_inst

Driver structure pointer

References ac_dev_inst::hw_dev, SLEEPMGR_BACKUP, and sleepmgr_lock_mode().

Referenced by run_ac_test().

void ac_enable_interrupt	(	struct ac_dev_inst *const	dev_inst,
		ac_interrupt_source_t	source
	)

Enable the specified ACIFC interrupt source.

Parameters

[out]	dev_inst	Driver structure pointer
[in]	source	Interrupt source to enable

References AC_INTERRUPT_CONVERSION_COMPLETED_0, AC_INTERRUPT_CONVERSION_COMPLETED_1, AC_INTERRUPT_CONVERSION_COMPLETED_2, AC_INTERRUPT_CONVERSION_COMPLETED_3, AC_INTERRUPT_CONVERSION_COMPLETED_4, AC_INTERRUPT_CONVERSION_COMPLETED_5, AC_INTERRUPT_CONVERSION_COMPLETED_6, AC_INTERRUPT_CONVERSION_COMPLETED_7, AC_INTERRUPT_STARTUP_TIME_ELAPSED_0, AC_INTERRUPT_STARTUP_TIME_ELAPSED_1, AC_INTERRUPT_STARTUP_TIME_ELAPSED_2, AC_INTERRUPT_STARTUP_TIME_ELAPSED_3, AC_INTERRUPT_STARTUP_TIME_ELAPSED_4, AC_INTERRUPT_STARTUP_TIME_ELAPSED_5, AC_INTERRUPT_STARTUP_TIME_ELAPSED_6, AC_INTERRUPT_STARTUP_TIME_ELAPSED_7, AC_INTERRUPT_WINDOW_0, AC_INTERRUPT_WINDOW_1, AC_INTERRUPT_WINDOW_2, AC_INTERRUPT_WINDOW_3, Assert, and ac_dev_inst::hw_dev.

Referenced by ac_set_callback().

static void ac_get_config_defaults ( struct ac_config *const  cfg )

inlinestatic

Initialize an ACIFC configuration structure to default values.

Note

This function should be called to prepare all new instances of ACIFC configuration structures before they are further modified by the user application.

The default configuration is as follows:

• Peripheral event trigger is disabled

Parameters

[out]

cfg

ACIFC configuration structure pointer

References Assert, and ac_config::event_trigger.

Referenced by run_ac_test().

static uint32_t ac_get_interrupt_mask ( struct ac_dev_inst *const  dev_inst )

inlinestatic

Get the ACIFC interrupt mask.

Parameters

[in]

dev_inst

Driver structure pointer

Returns

The ACIFC interrupt mask.

References ac_dev_inst::hw_dev.

Referenced by ac_interrupt_handler().

static uint32_t ac_get_interrupt_status ( struct ac_dev_inst *const  dev_inst )

inlinestatic

Get the ACIFC interrupt status.

Parameters

[in]

dev_inst

Driver structure pointer

Returns

The ACIFC interrupt status.

References ac_dev_inst::hw_dev.

Referenced by ac_interrupt_handler().

static uint32_t ac_get_status ( struct ac_dev_inst *const  dev_inst )

inlinestatic

Get the ACIFC status.

Parameters

[in]

dev_inst

Driver structure pointer

Returns

The ACIFC status.

References ac_dev_inst::hw_dev.

enum status_code ac_init	(	struct ac_dev_inst *const	dev_inst,
		Acifc *const	ac,
		struct ac_config *const	cfg
	)

Initialize the ACIFC module.

Note

Enables the ACIFC module's source clock.

Parameters

[out]	dev_inst	Driver structure pointer
[in]	ac	Module hardware register base address pointer
[in]	cfg	Module configuration structure pointer

Returns

Status of initialization.

Return values

STATUS_OK	Module initiated correctly
STATUS_ERR_DENIED	Module has already been enabled
STATUS_ERR_BUSY	Module is busy performing a comparison

References _ac_set_config(), Assert, ac_dev_inst::hw_dev, STATUS_ERR_BUSY, STATUS_ERR_DENIED, STATUS_OK, and sysclk_enable_peripheral_clock().

Referenced by run_ac_test().

static bool ac_is_comparison_done ( struct ac_dev_inst *const  dev_inst )

inlinestatic

Check if the ACIFC comparison is done.

Parameters

[in]

dev_inst

Driver structure pointer

Returns

The ACIFC comparison result.

Return values

false	ACIFC comparison has not completed
true	ACIFC comparison has completed

References ac_dev_inst::hw_dev.

void ac_set_callback	(	struct ac_dev_inst *const	dev_inst,
		ac_interrupt_source_t	source,
		ac_callback_t	callback,
		uint8_t	irq_level
	)

Set the ACIFC interrupt callback.

Parameters

[in]	dev_inst	Driver structure pointer
[in]	source	ACIFC interrupt source
[in]	callback	Interrupt callback function pointer
[in]	irq_level	Interrupt priority level

References ac_enable_interrupt(), and irq_register_handler.

Referenced by run_ac_test().

static void ac_user_trigger_single_comparison ( struct ac_dev_inst *const  dev_inst )

inlinestatic

Start a single ACIFC comparison.

Parameters

[in]

dev_inst

Driver structure pointer

References ac_dev_inst::hw_dev.

Referenced by run_ac_test().

static void ac_win_get_config_defaults ( struct ac_win_config *const  cfg )

inlinestatic

Initializes an ACIFC window configuration structure to default values.

Note

This function should be called to prepare all new instances of ACIFC window configuration structures before they are further modified by the user application.

The default configuration is as follows:

• Window mode is disabled
• Peripheral event from ACWOUT is disabled
• Generate the window peripheral event when the comparison is done
• Window interrupt enabled when the evaluation of the common input voltage is done

Parameters

[out]

cfg

ACIFC window configuration structure pointer

References AC_WIN_EVENT_MEASURE_DONE, AC_WIN_IS_WINDOW_COMP_DONE, Assert, ac_win_config::enable, ac_win_config::event_enable, ac_win_config::event_source, and ac_win_config::interrupt_setting.

void ac_win_set_config	(	struct ac_dev_inst *const	dev_inst,
		uint32_t	window,
		struct ac_win_config *	cfg
	)

Configure the specified ACIFC window.

Parameters

[in]	dev_inst	Driver structure pointer
[in]	window	ACIFC window number (range 0 to 3 inclusive)
[in]	cfg	ACIFC window configuration structure

References Assert, ac_win_config::enable, ac_win_config::event_enable, ac_win_config::event_source, ac_dev_inst::hw_dev, and ac_win_config::interrupt_setting.