CAC Interface

Interface for clock frequency accuracy measurements. More...

Data Structures
struct	cac_ref_clock_config_t
struct	cac_meas_clock_config_t
struct	cac_callback_args_t
struct	cac_cfg_t
struct	cac_api_t
struct	cac_instance_t

Typedefs
typedef void	cac_ctrl_t

Enumerations
enum	cac_event_t { CAC_EVENT_FREQUENCY_ERROR, CAC_EVENT_MEASUREMENT_COMPLETE, CAC_EVENT_COUNTER_OVERFLOW }
enum	cac_clock_type_t { CAC_CLOCK_MEASURED, CAC_CLOCK_REFERENCE }
enum	cac_clock_source_t {   CAC_CLOCK_SOURCE_MAIN_OSC = 0x00, CAC_CLOCK_SOURCE_SUBCLOCK = 0x01, CAC_CLOCK_SOURCE_HOCO = 0x02, CAC_CLOCK_SOURCE_MOCO = 0x03,   CAC_CLOCK_SOURCE_LOCO = 0x04, CAC_CLOCK_SOURCE_PCLKB = 0x05, CAC_CLOCK_SOURCE_IWDT = 0x06, CAC_CLOCK_SOURCE_MEAS_MAX = CAC_CLOCK_SOURCE_IWDT,   CAC_CLOCK_SOURCE_EXTERNAL = 0x07, CAC_CLOCK_SOURCE_REF_MAX = CAC_CLOCK_SOURCE_EXTERNAL }
enum	cac_ref_divider_t { CAC_REF_DIV_32 = 0x00, CAC_REF_DIV_128 = 0x01, CAC_REF_DIV_1024 = 0x02, CAC_REF_DIV_8192 = 0x03 }
enum	cac_ref_digfilter_t { CAC_REF_DIGITAL_FILTER_OFF = 0x00, CAC_REF_DIGITAL_FILTER_1 = 0x01, CAC_REF_DIGITAL_FILTER_4 = 0x02, CAC_REF_DIGITAL_FILTER_16 = 0x03 }
enum	cac_ref_edge_t { CAC_REF_EDGE_RISE = 0x00, CAC_REF_EDGE_FALL = 0x01, CAC_REF_EDGE_BOTH = 0x02 }
enum	cac_meas_divider_t { CAC_MEAS_DIV_1 = 0x00, CAC_MEAS_DIV_4 = 0x01, CAC_MEAS_DIV_8 = 0x02, CAC_MEAS_DIV_32 = 0x03 }

Detailed Description

Interface for clock frequency accuracy measurements.

Register definitions, common services and error codes.

Summary

The interface for the clock frequency accuracy measurement circuit (CAC) peripheral is used to check a system clock frequency with a reference clock signal by counting the number of pulses of the clock (system clock) to be measured.

Related SSP architecture topics:

• SSP Interfaces
• SSP Predefined Layers
• Using SSP Modules

CAC Interface description: Clock Accurate Circuit Driver

Typedef Documentation

cac_ctrl_t

typedef void cac_ctrl_t

CAC control block. Allocate an instance specific control block to pass into the CAC API calls.

Implemented as

• cac_instance_ctrl_t

Enumeration Type Documentation

cac_clock_source_t

enum cac_clock_source_t

Enumeration of the possible clock sources for both the reference and measurement clocks.

Enumerator
CAC_CLOCK_SOURCE_MAIN_OSC	Main clock oscillator.
CAC_CLOCK_SOURCE_SUBCLOCK	Sub-clock.
CAC_CLOCK_SOURCE_HOCO	HOCO (High speed on chip oscillator)
CAC_CLOCK_SOURCE_MOCO	MOCO (Middle speed on chip oscillator)
CAC_CLOCK_SOURCE_LOCO	LOCO (Middle speed on chip oscillator)
CAC_CLOCK_SOURCE_PCLKB	PCLKB (Peripheral Clock B)
CAC_CLOCK_SOURCE_IWDT	IWDT- Dedicated on-chip oscillator.
CAC_CLOCK_SOURCE_MEAS_MAX	Maximum measured clock.
CAC_CLOCK_SOURCE_EXTERNAL	Externally supplied measurement clock on CACREF pin.
CAC_CLOCK_SOURCE_REF_MAX	Maximum reference clock.

cac_clock_type_t

enum cac_clock_type_t

Enumeration of the two possible clocks.

Enumerator
CAC_CLOCK_MEASURED	Measurement clock.
CAC_CLOCK_REFERENCE	Reference clock.

cac_event_t

enum cac_event_t

Event types returned by the ISR callback when used in CAC interrupt mode

Enumerator
CAC_EVENT_FREQUENCY_ERROR	Frequency error.
CAC_EVENT_MEASUREMENT_COMPLETE	Measurement complete.
CAC_EVENT_COUNTER_OVERFLOW	Counter overflow.

cac_meas_divider_t

enum cac_meas_divider_t

Enumeration of available dividers for the measurement clock

Enumerator
CAC_MEAS_DIV_1	Measurement clock divided by 1.
CAC_MEAS_DIV_4	Measurement clock divided by 4.
CAC_MEAS_DIV_8	Measurement clock divided by 8.
CAC_MEAS_DIV_32	Measurement clock divided by 32.

cac_ref_digfilter_t

enum cac_ref_digfilter_t

Enumeration of available digital filter settings for an external reference clock.

Enumerator
CAC_REF_DIGITAL_FILTER_OFF	No digital filter on the CACREF pin for reference clock.
CAC_REF_DIGITAL_FILTER_1	Sampling clock for digital filter = measuring frequency.
CAC_REF_DIGITAL_FILTER_4	Sampling clock for digital filter = measuring frequency/4.
CAC_REF_DIGITAL_FILTER_16	Sampling clock for digital filter = measuring frequency/16.

cac_ref_divider_t

enum cac_ref_divider_t

Enumeration of available dividers for the reference clock.

Enumerator
CAC_REF_DIV_32	Reference clock divided by 32.
CAC_REF_DIV_128	Reference clock divided by 128.
CAC_REF_DIV_1024	Reference clock divided by 1024.
CAC_REF_DIV_8192	Reference clock divided by 8192.

cac_ref_edge_t

enum cac_ref_edge_t

Enumeration of available edge detect settings for the reference clock.

Enumerator
CAC_REF_EDGE_RISE	Rising edge detect for the Reference clock.
CAC_REF_EDGE_FALL	Falling edge detect for the Reference clock.
CAC_REF_EDGE_BOTH	Both Rising and Falling edges detect for the Reference clock.