/*
* ======== switchToWatchdogTimer ========
*
* Use 250ms watchdog timer interrupt to drive the Clock tick
* Stop the default Timer_A then start the watchdog timer.
*/
static void switchToWatchdogTimer()
{
Clock_TimerProxy_Handle clockTimer;
static Hwi_Handle wdtHwi = NULL;
/* Stop Timer_A currrently being used by Clock */
clockTimer = Clock_getTimerHandle();
Clock_TimerProxy_stop(clockTimer);
MAP_WDT_A_holdTimer();
if (wdtHwi == NULL) {
/* Create watchdog Timer Hwi */
wdtHwi = Hwi_create(19, clockTickFxn, NULL, NULL);
/* set WDT to use 32KHz input, 250ms period */
MAP_WDT_A_initIntervalTimer(WDT_A_CLOCKSOURCE_XCLK, WDT_A_CLOCKITERATIONS_8192);
}
/* don't allow deeper than DEEPSLEEP1 */
Power_setConstraint(PowerMSP432_DISALLOW_DEEPSLEEP_1);
/* Start watchdog Timer */
MAP_WDT_A_clearTimer();
MAP_WDT_A_startTimer();
/* hence, Clock_tick() will be called from 250ms watchdog timer interrupt */
}
/*
* ======== WatchdogMSP432_open ========
*/
Watchdog_Handle WatchdogMSP432_open(Watchdog_Handle handle,
Watchdog_Params *params)
{
uintptr_t key;
HwiP_Params hwiParams;
WatchdogMSP432_Object *object = handle->object;
WatchdogMSP432_HWAttrs const *hwAttrs = handle->hwAttrs;
/* If params are NULL use defaults. */
if (params == NULL) {
params = (Watchdog_Params *) &Watchdog_defaultParams;
}
/* Ensure a callbackFxn is specified if using watchdog in interval mode */
DebugP_assert((params->resetMode == Watchdog_RESET_ON) ||
(params->callbackFxn != NULL));
/* Don't allow preemption */
key = HwiP_disable();
/* Check if the Watchdog is open already with the HWAttrs */
if (object->isOpen) {
HwiP_restore(key);
DebugP_log1("Watchdog: Handle %x already in use.", (uintptr_t) handle);
return (NULL);
}
object->isOpen = true;
HwiP_restore(key);
/*
* Add power management support - Disable performance transitions while
* opening the driver.
*/
Power_setConstraint(PowerMSP432_DISALLOW_PERF_CHANGES);
if (params->resetMode == Watchdog_RESET_ON ||
hwAttrs->clockSource == WDT_A_CLOCKSOURCE_SMCLK ||
hwAttrs->clockSource == WDT_A_CLOCKSOURCE_ACLK) {
/*
* Do not support power modes lower than LPM0 if in watchdog mode or
* in interval mode and using SMCLK or ACLK as clock sources.
* Additionally, LPM3.5 cannot be reached.
*/
Power_setConstraint(PowerMSP432_DISALLOW_DEEPSLEEP_0);
Power_setConstraint(PowerMSP432_DISALLOW_SHUTDOWN_0);
}
else {
/*
* Interval mode and not using SMCLK and ACLK as clock sources. Can
* be configured as a LPM3.5 wake up source, so we do not set the
* SHUTDOWN_0 constraint.
*/
Power_setConstraint(PowerMSP432_DISALLOW_DEEPSLEEP_1);
}
/* SHUTDOWN_1 (LPM4.5) not supported while driver is open */
Power_setConstraint(PowerMSP432_DISALLOW_SHUTDOWN_1);
/* Construct Hwi object for watchdog */
if (params->callbackFxn) {
HwiP_Params_init(&hwiParams);
hwiParams.arg = (uintptr_t) handle;
hwiParams.priority = hwAttrs->intPriority;
object->hwiHandle = HwiP_create(hwAttrs->intNum, params->callbackFxn,
&hwiParams);
if (!object->hwiHandle) {
DebugP_log0("Watchdog: HwiP_create() failed");
Power_releaseConstraint(PowerMSP432_DISALLOW_PERF_CHANGES);
WatchdogMSP432_close(handle);
return (NULL);
}
}
/* Configure and initialize WDT */
object->resetMode = params->resetMode;
if (object->resetMode == Watchdog_RESET_ON) {
MAP_WDT_A_initWatchdogTimer(hwAttrs->clockSource, hwAttrs->clockDivider);
}
else {
MAP_WDT_A_initIntervalTimer(hwAttrs->clockSource, hwAttrs->clockDivider);
}
MAP_WDT_A_startTimer();
/* Allow performance level changes */
Power_releaseConstraint(PowerMSP432_DISALLOW_PERF_CHANGES);
DebugP_log1("Watchdog: (0x%x) opened and enabled.", (uintptr_t) handle);
/* Return handle of the Watchdog object */
return (handle);
}