MityDSP::tcDspWatchdog Class Reference

Static class to provide the ability to enable and manage the watchdog timer core of the MityDSP. More...

#include <core/DspWatchdog.h>

List of all members.

Public Types
typedef void(*	tfWatchdogCallback )(void)
	Prototype for the tcDspWatchdog ISR callback.
typedef void(*	tfWatchdogCallbackWithArg )(void *)
Static Public Member Functions
static bool	enable (bool abEnableNmi, bool abEnableRst, unsigned int anTimeoutMsec=15000, unsigned int anNmiTimeoutMsec=100)
	This routine is used to enable or disable the MityDSP watchdog, which is disabled by default.
static void	reset (unsigned int anResetTicks=0, bool abClearConditions=true)
	This routine must be called periodically by application software to reset the MityDSP watchdog timer.
static void	register_callback (tfWatchdogCallback apCallback=NULL)
	This routine registers an ISR callback for the watchdog NMI interrupt.
static void	register_callback (tfWatchdogCallbackWithArg apCallback=NULL, void *apUserArg=NULL)
	This routine registers an ISR callback for the watchdog NMI interrupt.
static void	nmi_handler (void)
	This routine is installed as an NMI handler whenever the MityDSP watchdog timer's NMI interrupt is enabled.

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Detailed Description

Static class to provide the ability to enable and manage the watchdog timer core of the MityDSP.

The MityDSP watchdog timer can be configured to reset the MityDSP processor if the timer is not reset periodically.

See also:

tcDspWatchdog Page

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Member Typedef Documentation

typedef void(* MityDSP::tcDspWatchdog::tfWatchdogCallback)(void)

Prototype for the tcDspWatchdog ISR callback.

typedef void(* MityDSP::tcDspWatchdog::tfWatchdogCallbackWithArg)(void *)

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Member Function Documentation

bool tcDspWatchdog::enable	(	bool	abEnableNmi,
		bool	abEnableRst,
		unsigned int	anTimeoutMsec = 15000,
		unsigned int	anNmiTimeoutMsec = 100
	)			[static]

This routine is used to enable or disable the MityDSP watchdog, which is disabled by default.

The watchdog may be configured to raise either NMI, or RST. NMI allows an application-specific callback to be activated (for post-mortem data collection possibly). RST will cause the MityDSP to be reset. If both are enabled, NMI is raised after the first timeout, and RST after the second.

Timeouts are provided for normal watchdog reset, and a second timeout (possibly shorter) to apply in the NMI handler if the watchdog RST is also enabled.

Note:

Attempts to enable reset when running a debug version of the the core library (DspCoreD.lib) will not be honored. This prevents the watchdog timer from resetting the board during debugging.

Parameters:

[in]	abEnableNmi	Enable watchdog NMI after a timeout.
[in]	abEnableRst	Enable watchdog RST after a timeout.
[in]	anTimeoutMsec	Watchdog timer reset value (100-6553600 msec).
[in]	anNmiTimeoutMsec	Watchdog timer reset value between an NMI and a RST event (100-6553600 msec).

Returns:

True if either watchdog NMI or RST is enabled.

void tcDspWatchdog::reset	(	unsigned int	anResetTicks = 0,
		bool	abClearConditions = true
	)			[static]

This routine must be called periodically by application software to reset the MityDSP watchdog timer.

Called with no parameters, the watchdog countdown value is reset to the value computed when the watchdog functionality was enabled. If a non-zero value is provided, the countdown register is set to the provided value.

Parameters:

[in]	anResetTicks	Value to set the watchdog countdown timer to (default: 0 - use configured setting)
[in]	abClearConditions	Indicates whether any NMI/RST conditions should be cleared (default: true)

Returns:

None.

void tcDspWatchdog::register_callback

(

tfWatchdogCallback

afCallback = NULL

)

[static]

This routine registers an ISR callback for the watchdog NMI interrupt.

It assumes that no other NMI handlers are in use in the system.

Note:

The callback must not call any DSP/BIOS functions, nor any MityDSP library functions that require DSP/BIOS calls. The routine is called in the context of an NMI.

Parameters:

[in]

afCallback

The NMI callback function (NULL for none).

Returns:

None.

void tcDspWatchdog::register_callback	(	tfWatchdogCallbackWithArg	afCallback = NULL,
		void *	apUserArg = NULL
	)			[static]

This routine registers an ISR callback for the watchdog NMI interrupt.

It assumes that no other NMI handlers are in use in the system.

Note:

The callback must not call any DSP/BIOS functions, nor any MityDSP library functions that require DSP/BIOS calls. The routine is called in the context of an NMI.

Parameters:

[in]	afCallback	The NMI callback function (NULL for none).
[in]	apUserArg	An argument to be supplied with the callback.

Returns:

None.

void tcDspWatchdog::nmi_handler

(

void

)

[static]

This routine is installed as an NMI handler whenever the MityDSP watchdog timer's NMI interrupt is enabled.

If an application-specific callback has been previously registered, this routine is first called. Following this call, the watchdog timer is reset. If the watchdog is also configured to assert RST, the special "final" timeout value is used to reset the watchdog, otherwise the normal reset timeout is used.

This allows a RST to be triggered quickly after the NMI, if desired.

Returns:

None.