CAC

Driver for the Clock Frequency Accuracy Measurement Circuit (CAC). More...

Data Structures
struct	cac_instance_ctrl_t

Functions
ssp_err_t	R_CAC_Open (cac_ctrl_t *const p_api_ctrl, cac_cfg_t const *const p_cfg)
	Initialize the CAC peripheral. More...
ssp_err_t	R_CAC_Close (cac_ctrl_t *const p_api_ctrl)
	Release any resources that were allocated by the Open() or any subsequent CAC operations. Implements r_cac_t::close. More...
ssp_err_t	R_CAC_StopMeasurement (cac_ctrl_t *const p_api_ctrl)
	Stop the CAC measurement process. Implements r_cac_t::stopMeasurement. More...
ssp_err_t	R_CAC_StartMeasurement (cac_ctrl_t *const p_api_ctrl)
	Start the CAC measurement process. Implements r_cac_t::startMeasurement. More...
ssp_err_t	R_CAC_Reset (cac_ctrl_t *const p_api_ctrl)
	Resets the Overflow, Measurement End and Frequency Error interrupt flags. This will clear any of the CASTR status bits that have been set, but only if the CFME bit is off (Not measuring). Implements r_cac_t::reset. More...
ssp_err_t	R_CAC_Read (cac_ctrl_t *const p_api_ctrl, uint8_t *const p_status, uint16_t *const p_counter)
	Read and return the CAC status and counter registers. Implements r_cac_t::read. More...
ssp_err_t	R_CAC_VersionGet (ssp_version_t *const p_version)
	Get the API and code version information. More...

Detailed Description

Driver for the Clock Frequency Accuracy Measurement Circuit (CAC).

Summary

This module supports the CAC peripheral.

Function Documentation

R_CAC_Close()

ssp_err_t R_CAC_Close

(

cac_ctrl_t *const

p_ctrl

)

Release any resources that were allocated by the Open() or any subsequent CAC operations. Implements r_cac_t::close.

Return values

SSP_SUCCESS	Successful close.
SSP_ERR_ASSERTION	NULL provided for p_ctrl or p_cfg.
SSP_ERR_NOT_OPEN	R_CAC_Open() has not been successfully called.

// Example code
// Create a variable for the error
ssp_err_t   err;

// Define a control block structure used in the API calls.
cac_ctrl_t ctrl;

err = R_CAC_Close(&ctrl);

Eliminate warning if parameter checking is disabled.

Disable interrupts in the peripheral and NVIC

Disable interrupts in NVIC.

Disable the CAC ints.

Stop measuring.

Power down peripheral.

Return the hardware lock for the CAC.

R_CAC_Open()

ssp_err_t R_CAC_Open	(	cac_ctrl_t *const	p_ctrl,
		cac_cfg_t const *const	p_cfg
	)

Initialize the CAC peripheral.

The Open function applies power to the CAC peripheral, checks/sets the interrupt priority, and configures the CAC based on the provided user configuration settings. If a user defined callback function has been provided in the configuration, then the CAC interrupt(s) will be enabled and the user callback function called accordingly. Implements r_cac_t::open.

Return values

SSP_SUCCESS	CAC is available and available for measurement(s).
SSP_ERR_ASSERTION	Null Pointer.
SSP_ERR_INVALID_ARGUMENT	One or more configuration options are invalid.
SSP_ERR_HW_LOCKED	Hardware lock for CAC peripheral is already taken.
SSP_ERR_INVALID_CAC_REF_CLOCK	Measured clock rate smaller than reference clock rate.

Returns

See Common Error Codes or functions called by this function for other possible return codes. This function calls:

• fmi_api_t::productFeatureGet
• fmi_api_t::eventInfoGet

Note

There is only a single CAC peripheral. It is not reentrant.

// Example code
// Create a variable for the error
ssp_err_t   err;

// Define a control block structure used in the API calls.
cac_ctrl_t ctrl;

// Define a configuration structure used in the API calls.
cac_cfg_t g_cac_example_cfg;

// Init the CGC and start the HOCO and LOCO clocks.
err = R_CGC_Init();

err = R_CGC_ClockStart(CGC_CLOCK_HOCO, &clock_config);
err = R_CGC_ClockStart(CGC_CLOCK_LOCO, &clock_config);
   

// Specify the parameters we are using
g_cac_example_cfg.callback = NULL,
g_cac_example_cfg.p_context = 0,
g_cac_example_cfg.p_extend = NULL,
g_cac_example_cfg.continuous_mode = false,        // measurement does not continuously restart after completing.
g_cac_example_cfg.mei_interrupt_enabled = false;  // Measurement complete interrupt disabled
g_cac_example_cfg.ovf_interrupt_enabled = false;  // Overflow interrupt is disabled
g_cac_example_cfg.ferr_interrupt_enabled = false; // Frequency Error interrupt is disabled

g_cac_example_cfg.cac_ref_clock.digfilter = CAC_REF_DIGF_OFF;  // No digital filter
g_cac_example_cfg.cac_ref_clock.edge = CAC_REF_EDGE_RISE;      // Rising edge detect
g_cac_example_cfg.cac_meas_clock.clock = CAC_CLOCK_SOURCE_HOCO;  // We want to measure HOCO (24 MHz)
g_cac_example_cfg.cac_meas_clock.divider = CAC_MEAS_DIV_1;       // No divisor on the measurement clock
g_cac_example_cfg.cac_ref_clock.clock = CAC_CLOCK_SOURCE_LOCO;   // Our reference clock will LOCO (32.768 kHz)
g_cac_example_cfg.cac_ref_clock.divider = CAC_REF_DIV_32;        // Minimum divider is 32, so effective freq  = 1024 Hz

 err = R_CAC_Open(&ctrl, &g_cac_example_cfg);

g_cac_version is accessed by the ASSERT macro only and so compiler toolchain can issue a warning that they are not accessed. The code below eliminates this warning and also ensures these data structures are not optimised away.

Eliminate warning if parameter checking is disabled.

Take the hardware lock for the CAC.

Setup the interrupt vectors and priorities

Return the hardware lock for the CAC.

Apply power to the peripheral

Configure the CAC per the configuration.

Store the callback and context information

Mark driver as open by initializing it to "CAC" - its ASCII equivalent.

R_CAC_Read()

ssp_err_t R_CAC_Read	(	cac_ctrl_t *const	p_ctrl,
		uint8_t *const	p_status,
		uint16_t *const	p_counter
	)

Read and return the CAC status and counter registers. Implements r_cac_t::read.

Return values

SSP_SUCCESS	CAC read successful.
SSP_ERR_ASSERTION	NULL provided for p_ctrl or p_cfg.
SSP_ERR_NOT_OPEN	R_CAC_Open() has not been successfully called.

// Example code

// Create a variable for the error and storage for the CAC count and status
ssp_err_t   err;
uint8_t   cac_status;
uint16_t  cac_counter;

// Define a control block structure used in the API calls.
cac_ctrl_t ctrl;

err =  R_CAC_Read(&ctrl, &cac_status,  &cac_counter);

Eliminate warning if parameter checking is disabled.

R_CAC_Reset()

ssp_err_t R_CAC_Reset

(

cac_ctrl_t *const

p_ctrl

)

Resets the Overflow, Measurement End and Frequency Error interrupt flags. This will clear any of the CASTR status bits that have been set, but only if the CFME bit is off (Not measuring). Implements r_cac_t::reset.

Return values

SSP_SUCCESS	CAC reset completed.
SSP_ERR_ASSERTION	NULL provided for p_ctrl or p_cfg.
SSP_ERR_NOT_OPEN	R_CAC_Open() has not been successfully called.

// Example code

// Create a variable for the error
ssp_err_t   err;

// Define a control block structure used in the API calls.
 cac_ctrl_t ctrl;

// Start the measurement process
err = R_CAC_Reset(&ctrl);

Eliminate warning if parameter checking is disabled.

Reset the CAC.

R_CAC_StartMeasurement()

ssp_err_t R_CAC_StartMeasurement

(

cac_ctrl_t *const

p_ctrl

)

Start the CAC measurement process. Implements r_cac_t::startMeasurement.

Return values

SSP_SUCCESS	CAC measurement started.
SSP_ERR_ASSERTION	NULL provided for p_ctrl or p_cfg.
SSP_ERR_NOT_OPEN	R_CAC_Open() has not been successfully called.
SSP_ERR_CLOCK_INACTIVE	Either the provided Measurement or Reference clock is not running

Returns

See Common Error Codes or functions called by this function for other possible return codes. This function calls:

• cgc_api_t::clockCheck

// Example code

// Create a variable for the error
ssp_err_t   err;

// Define a control block structure used in the API calls.
 cac_ctrl_t ctrl;

// Start the measurement process
err = R_CAC_StartMeasurement(&ctrl);

Eliminate warnings if parameter checking is disabled.

Start measuring.

R_CAC_StopMeasurement()

ssp_err_t R_CAC_StopMeasurement

(

cac_ctrl_t *const

p_ctrl

)

Stop the CAC measurement process. Implements r_cac_t::stopMeasurement.

Return values

SSP_SUCCESS	CAC measuring has been stopped.
SSP_ERR_ASSERTION	NULL provided for p_ctrl or p_cfg.
SSP_ERR_NOT_OPEN	R_CAC_Open() has not been successfully called.

// Example code
// Create a variable for the error
ssp_err_t   err;

// Define a control block structure used in the API calls.
 cac_ctrl_t ctrl;

// Stop the measurement process
err = R_CAC_StopMeasurement(&ctrl);

Eliminate warning if parameter checking is disabled.

Stop measuring.

R_CAC_VersionGet()

ssp_err_t R_CAC_VersionGet

(

ssp_version_t *const

p_version

)

Get the API and code version information.

Return values

SSP_SUCCESS

Version info returned.

Note

This function is reentrant.

// Example code

// Create a variable for the error
ssp_err_t   err;

// Create a variable for the version information
ssp_version_t   version;

// Get the current counter value
err = R_CAC_VersionGet(&version);