WDT Interface

Detailed Description

Interface for watch dog timer functions.

Summary

The WDT interface for the Watchdog Timer (WDT) peripheral provides watchdog functionality including resetting the device or generating an interrupt.

Data Structures
struct	wdt_callback_args_t
struct	wdt_timeout_values_t
struct	wdt_cfg_t
struct	wdt_api_t
struct	wdt_instance_t

Typedefs
typedef void	wdt_ctrl_t

Enumerations
enum	wdt_timeout_t
enum	wdt_clock_division_t
enum	wdt_window_start_t
enum	wdt_window_end_t
enum	wdt_reset_control_t
enum	wdt_stop_control_t
enum	wdt_status_t

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Data Structure Documentation

wdt_callback_args_t

struct wdt_callback_args_t

Callback function parameter data

Data Fields
void *	p_context	Placeholder for user data. Set in wdt_api_t::open function in wdt_cfg_t.

wdt_timeout_values_t

struct wdt_timeout_values_t

WDT timeout data. Used to return frequency of WDT clock and timeout period

Data Fields
uint32_t	clock_frequency_hz	Frequency of watchdog clock after divider.
uint32_t	timeout_clocks	Timeout period in units of watchdog clock ticks.

wdt_cfg_t

struct wdt_cfg_t

WDT configuration parameters.

Data Fields
wdt_timeout_t	timeout
	Timeout period.
wdt_clock_division_t	clock_division
	Clock divider.
wdt_window_start_t	window_start
	Refresh permitted window start position.
wdt_window_end_t	window_end
	Refresh permitted window end position.
wdt_reset_control_t	reset_control
	Select NMI/IRQ or reset generated on underflow.
wdt_stop_control_t	stop_control
	Select whether counter operates in sleep mode.
void(*	p_callback )(wdt_callback_args_t *p_args)
	Callback provided when a WDT ISR occurs.
void *	p_context
void const *	p_extend
	Placeholder for user extension.

Field Documentation

p_context

void* wdt_cfg_t::p_context

Placeholder for user data. Passed to the user callback in wdt_callback_args_t.

wdt_api_t

struct wdt_api_t

WDT functions implemented at the HAL layer will follow this API.

Data Fields
fsp_err_t(*	open )(wdt_ctrl_t *const p_ctrl, wdt_cfg_t const *const p_cfg)
fsp_err_t(*	refresh )(wdt_ctrl_t *const p_ctrl)
fsp_err_t(*	statusGet )(wdt_ctrl_t *const p_ctrl, wdt_status_t *const p_status)
fsp_err_t(*	statusClear )(wdt_ctrl_t *const p_ctrl, const wdt_status_t status)
fsp_err_t(*	counterGet )(wdt_ctrl_t *const p_ctrl, uint32_t *const p_count)
fsp_err_t(*	timeoutGet )(wdt_ctrl_t *const p_ctrl, wdt_timeout_values_t *const p_timeout)
fsp_err_t(*	callbackSet )(wdt_ctrl_t *const p_ctrl, void(*p_callback)(wdt_callback_args_t *), void *const p_context, wdt_callback_args_t *const p_callback_memory)

Field Documentation

open

fsp_err_t(* wdt_api_t::open) (wdt_ctrl_t *const p_ctrl, wdt_cfg_t const *const p_cfg)

Initialize the WDT in register start mode. In auto-start mode (Supported devices only) with NMI output it registers the NMI callback.

Parameters

[in]	p_ctrl	Pointer to control structure.
[in]	p_cfg	Pointer to pin configuration structure.

refresh

fsp_err_t(* wdt_api_t::refresh) (wdt_ctrl_t *const p_ctrl)

Refresh the watchdog timer.

Parameters

[in]

p_ctrl

Pointer to control structure.

statusGet

fsp_err_t(* wdt_api_t::statusGet) (wdt_ctrl_t *const p_ctrl, wdt_status_t *const p_status)

Read the status of the WDT.

Parameters

[in]	p_ctrl	Pointer to control structure.
[out]	p_status	Pointer to variable to return status information through.

statusClear

fsp_err_t(* wdt_api_t::statusClear) (wdt_ctrl_t *const p_ctrl, const wdt_status_t status)

Clear the status flags of the WDT.

Parameters

[in]	p_ctrl	Pointer to control structure.
[in]	status	Status condition(s) to clear.

counterGet

fsp_err_t(* wdt_api_t::counterGet) (wdt_ctrl_t *const p_ctrl, uint32_t *const p_count)

Read the current WDT counter value.

Parameters

[in]	p_ctrl	Pointer to control structure.
[out]	p_count	Pointer to variable to return current WDT counter value.

timeoutGet

fsp_err_t(* wdt_api_t::timeoutGet) (wdt_ctrl_t *const p_ctrl, wdt_timeout_values_t *const p_timeout)

Read the watchdog timeout values.

Parameters

[in]	p_ctrl	Pointer to control structure.
[out]	p_timeout	Pointer to structure to return timeout values.

callbackSet

fsp_err_t(* wdt_api_t::callbackSet) (wdt_ctrl_t *const p_ctrl, void(*p_callback)(wdt_callback_args_t *), void *const p_context, wdt_callback_args_t *const p_callback_memory)

Specify callback function and optional context pointer and working memory pointer.

Parameters

[in]	p_ctrl	Pointer to the WDT control block.
[in]	p_callback	Callback function
[in]	p_context	Pointer to send to callback function
[in]	p_callback_memory	Pointer to volatile memory where callback structure can be allocated. Callback arguments allocated here are only valid during the callback.

wdt_instance_t

struct wdt_instance_t

This structure encompasses everything that is needed to use an instance of this interface.

Data Fields
wdt_ctrl_t *	p_ctrl	Pointer to the control structure for this instance.
wdt_cfg_t const *	p_cfg	Pointer to the configuration structure for this instance.
wdt_api_t const *	p_api	Pointer to the API structure for this instance.

Typedef Documentation

wdt_ctrl_t

typedef void wdt_ctrl_t

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

Enumeration Type Documentation

wdt_timeout_t

enum wdt_timeout_t

WDT time-out periods.

Enumerator
WDT_TIMEOUT_128	128 clock cycles
WDT_TIMEOUT_512	512 clock cycles
WDT_TIMEOUT_1024	1024 clock cycles
WDT_TIMEOUT_2048	2048 clock cycles
WDT_TIMEOUT_4096	4096 clock cycles
WDT_TIMEOUT_8192	8192 clock cycles
WDT_TIMEOUT_16384	16384 clock cycles

wdt_clock_division_t

enum wdt_clock_division_t

WDT clock division ratio.

Enumerator
WDT_CLOCK_DIVISION_1	CLK/1.
WDT_CLOCK_DIVISION_4	CLK/4.
WDT_CLOCK_DIVISION_16	CLK/16.
WDT_CLOCK_DIVISION_32	CLK/32.
WDT_CLOCK_DIVISION_64	CLK/64.
WDT_CLOCK_DIVISION_128	CLK/128.
WDT_CLOCK_DIVISION_256	CLK/256.
WDT_CLOCK_DIVISION_512	CLK/512.
WDT_CLOCK_DIVISION_2048	CLK/2048.
WDT_CLOCK_DIVISION_8192	CLK/8192.

wdt_window_start_t

enum wdt_window_start_t

WDT refresh permitted period window start position.

Enumerator
WDT_WINDOW_START_25	Start position = 25%.
WDT_WINDOW_START_50	Start position = 50%.
WDT_WINDOW_START_75	Start position = 75%.
WDT_WINDOW_START_100	Start position = 100%.

wdt_window_end_t

enum wdt_window_end_t

WDT refresh permitted period window end position.

Enumerator
WDT_WINDOW_END_75	End position = 75%.
WDT_WINDOW_END_50	End position = 50%.
WDT_WINDOW_END_25	End position = 25%.
WDT_WINDOW_END_0	End position = 0%.

wdt_reset_control_t

enum wdt_reset_control_t

WDT Counter underflow and refresh error control.

Enumerator
WDT_RESET_CONTROL_NMI	NMI/IRQ request when counter underflows.
WDT_RESET_CONTROL_RESET	Reset request when counter underflows.

wdt_stop_control_t

enum wdt_stop_control_t

WDT Counter operation in sleep mode.

Enumerator
WDT_STOP_CONTROL_DISABLE	Count will not stop when device enters sleep mode.
WDT_STOP_CONTROL_ENABLE	Count will automatically stop when device enters sleep mode.

wdt_status_t

enum wdt_status_t

WDT status

Enumerator
WDT_STATUS_NO_ERROR	No status flags set.
WDT_STATUS_UNDERFLOW	Underflow flag set.
WDT_STATUS_REFRESH_ERROR	Refresh error flag set. Refresh outside of permitted window.
WDT_STATUS_UNDERFLOW_AND_REFRESH_ERROR	Underflow and refresh error flags set.
WDT_STATUS_OVERFLOW	Overflow flag set.