RSTC Interface

Driver API for RSTC (plib_rstc.h) More...

Typedefs
typedef void(*	RSTC_CALLBACK) (void)
	User Reset interrupt callback function type.

Functions
bool	RSTC_EnableUserReset (void)
	Enable User Reset on a low level on NRST.
bool	RSTC_DisableUserReset (void)
	Disable User Reset on a low level on NRST.
bool	RSTC_EnableUserResetInterrupt (void)
	Enable the User Reset interrupt.
bool	RSTC_DisableUserResetInterrupt (void)
	Disable the User Reset interrupt.
bool	RSTC_SetExternalResetLength (uint8_t length)
	Set the External Reset Length.
bool	RSTC_AssertProcessorReset (void)
	Command a processor reset.
bool	RSTC_AssertExternalReset (void)
	Command an external reset (RSTC_CR.EXTRST).
bool	RSTC_NrstLevelIsHigh (void)
	Report whether the NRST pin is currently sampled high (RSTC_SR.NRSTL).
uint32_t	RSTC_ReadResetType (void)
	Read the cause of the last processor reset.
bool	RSTC_UserResetIsDetected (void)
	Report whether a User Reset has been detected (RSTC_SR.URSTS).
bool	RSTC_SoftwareResetIsInProgress (void)
	Report whether a software reset command is currently in progress (RSTC_SR.SRCMP).
void	RSTC_RegisterUserResetCallback (RSTC_CALLBACK callback)
	Register a callback to be invoked from RSTC_Handler() on a User Reset interrupt event.
void	RSTC_ClearUserResetInterrupt (void)
	Clear the User Reset interrupt.

Description

Driver API for RSTC (plib_rstc.h)

Usage Example

The following example demonstrates typical usage of the RSTC peripheral:

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 *
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 * and any derivatives exclusively with Microchip products. It is your
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 *******************************************************************************/
/*******************************************************************************
* @file configure_rstc.c
*
* @brief Template for Reset Controller(RSTC) module.
*
* @details Example configuration for RSTC User Reset notification via callback.
********************************************************************************/
 
#include "plib_rstc.h"
#include <stdint.h>
 
static volatile bool rstc_user_reset_triggered = false;
 
static void UserResetCallback(void)
{
    rstc_user_reset_triggered = true;
    //user operation (e.g., log event, graceful shutdown, notify supervisor)
}
 
int32_t configure_rstc(void)
{
    /* External Reset Length (ERSTL, 0-15): NRST is held low for
     * 2^(ERSTL+1) SLOW_CLK cycles when RSTC_AssertExternalReset() runs. */
    const uint8_t rstc_external_reset_length = 5U;
 
    /* Disable automatic reset-on-NRST so the interrupt path below notifies
     * software instead. */
    (void)RSTC_DisableUserReset();
 
    /* Shape the NRST pulse used by RSTC_AssertExternalReset(). */
    (void)RSTC_SetExternalResetLength(rstc_external_reset_length);
 
    /* Register callback handler for the User Reset event. */
    RSTC_RegisterUserResetCallback(&UserResetCallback);
 
    /* Enable the User Reset interrupt (URSTIEN = 1). */
    (void)RSTC_EnableUserResetInterrupt();
 
    /* Enable RSTC interrupt in NVIC. */
    NVIC_EnableIRQ(RSTC_IRQn);
 
    return 0;
}

Typedef Documentation

RSTC_CALLBACK

typedef void(* RSTC_CALLBACK) (void)

User Reset interrupt callback function type.

Function Documentation

RSTC_AssertExternalReset()

bool RSTC_AssertExternalReset

(

void

)

Command an external reset (RSTC_CR.EXTRST).

Asserts the NRST pin low for the duration configured by RSTC_MR.ERSTL. No effect if a software reset command is already in progress. Reading RSTC_SR to check this also clears RSTC_SR.URSTS.

Returns

true if the reset command was issued, false if a software reset command was already in progress.

RSTC_AssertProcessorReset()

bool RSTC_AssertProcessorReset

(

void

)

Command a processor reset.

Resets the processor and all embedded peripherals. No effect if a software reset command is already in progress. Reading RSTC_SR to check this also clears RSTC_SR.URSTS.

Returns

true if the reset command was issued, false if a software reset command was already in progress.

RSTC_ClearUserResetInterrupt()

void RSTC_ClearUserResetInterrupt

(

void

)

Clear the User Reset interrupt.

Reading RSTC_SR clears RSTC_SR.URSTS, and with it the RSTC interrupt line.

RSTC_DisableUserReset()

bool RSTC_DisableUserReset

(

void

)

Disable User Reset on a low level on NRST.

Returns

true if RSTC_MR was written, false if write protection is active.

RSTC_DisableUserResetInterrupt()

bool RSTC_DisableUserResetInterrupt

(

void

)

Disable the User Reset interrupt.

Preserves the current URSTEN and ERSTL fields.

Returns

true if RSTC_MR was written, false if write protection is active.

RSTC_EnableUserReset()

bool RSTC_EnableUserReset

(

void

)

Enable User Reset on a low level on NRST.

Returns

true if RSTC_MR was written, false if write protection is active.

RSTC_EnableUserResetInterrupt()

bool RSTC_EnableUserResetInterrupt

(

void

)

Enable the User Reset interrupt.

Only asserts the RSTC interrupt line when URSTEN = 0. Preserves the current URSTEN and ERSTL fields.

Returns

true if RSTC_MR was written, false if write protection is active.

RSTC_NrstLevelIsHigh()

bool RSTC_NrstLevelIsHigh

(

void

)

Report whether the NRST pin is currently sampled high (RSTC_SR.NRSTL).

Reading RSTC_SR clears RSTC_SR.URSTS.

Returns

true if NRST is currently high, false if low.

RSTC_ReadResetType()

uint32_t RSTC_ReadResetType

(

void

)

Read the cause of the last processor reset.

Reading RSTC_SR clears RSTC_SR.URSTS.

Returns

The raw RSTTYP field value: 0=GENERAL_RST, 1=BACKUP_RST, 2=WDT_RST, 3=SOFT_RST, 4=USER_RST.

RSTC_RegisterUserResetCallback()

void RSTC_RegisterUserResetCallback

(

RSTC_CALLBACK

callback

)

Register a callback to be invoked from RSTC_Handler() on a User Reset interrupt event.

Only relevant when RSTC_MR.URSTEN = 0 and RSTC_MR.URSTIEN = 1 (see RSTC_DisableUserReset() and RSTC_EnableUserResetInterrupt()).

Parameters

[in]

callback

Function to invoke, or NULL to unregister.

RSTC_SetExternalResetLength()

bool RSTC_SetExternalResetLength

(

uint8_t

length

)

Set the External Reset Length.

NRST is held low for 2^(ERSTL+1) SLOW_CLK cycles. Must be non-zero for a correctly shaped Watchdog Timer reset; ERSTL defaults to 0 at power-up.

Parameters

[in]

length

External Reset Length (ERSTL, 0-15).

Returns

true if RSTC_MR was written, false if write protection is active.

RSTC_SoftwareResetIsInProgress()

bool RSTC_SoftwareResetIsInProgress

(

void

)

Report whether a software reset command is currently in progress (RSTC_SR.SRCMP).

Reading RSTC_SR clears RSTC_SR.URSTS.

Returns

true if a software reset command is in progress, false if RSTC is ready for a new one.

RSTC_UserResetIsDetected()

bool RSTC_UserResetIsDetected

(

void

)

Report whether a User Reset has been detected (RSTC_SR.URSTS).

Reading RSTC_SR clears RSTC_SR.URSTS.

Returns

true if a high-to-low transition on NRST was detected.