/*
* ======== Timer_getExpiredCounts ========
*/
UInt32 Timer_getExpiredCounts(Timer_Object *obj)
{
UInt key;
UInt32 count1, count2;
Bool countFlag;
key = Hwi_disable();
count1 = Timer_getCount(obj);
if (obj->id == 0) { /* SysTick Timer */
countFlag = Hwi_nvic.STCSR & 0x00010000;
}
else { /* CTM Timer */
/* Test corresponding Int pending flag */
countFlag = Hwi_nvic.ISPR[0] & (1 << (obj->intNum - 16));
}
count2 = Timer_getCount(obj);
Hwi_restore(key);
if (obj->id == 0) { /* SysTick Timer */
if ((count1 > count2) && countFlag) {
return (obj->period - count1 + Timer_getPeriod(obj));
}
else {
return (obj->period - count1);
}
}
else { /* CTM Timer */
if (count2 < count1 && countFlag) {
return (count1 + Timer_getPeriod(obj));
}
else {
return (count1) ;
}
}
}
/*
* ======== Timer_getExpiredCounts ========
*/
UInt32 Timer_getExpiredCounts(Timer_Object *obj)
{
/* if timer running with RunMode_DYNAMIC ... */
if (obj->runMode == Timer_RunMode_DYNAMIC) {
TimerRegs *timer;
UInt32 result;
UInt32 count;
UInt32 thresh;
UInt32 period;
UInt32 prev;
Bool intrFlag1;
Bool intrFlag2;
timer = (TimerRegs *)Timer_module->device[obj->id].baseAddr;
intrFlag1 = timer->tisr & TIMER_IRQSTATUS_MAT_IT_FLAG;
count = Timer_getCount(obj);
intrFlag2 = timer->tisr & TIMER_IRQSTATUS_MAT_IT_FLAG;
prev = obj->prevThreshold;
/* was interrupt pending before read the count? */
if (intrFlag1) {
thresh = timer->tmar; /* threshold for interrupt */
period = Timer_getPeriod(obj); /* period count */
/* threshold reached; no wrap thru zero yet */
if (count >= thresh) {
result = (count - thresh) + period;
}
/* threshold reached; count has wrapped thru zero */
else {
result = (0xffffffff - thresh + 1) + count + period;
}
}
/* new interrupt now pending, when wasn't before read the count */
else if (intrFlag2) {
result = Timer_getPeriod(obj); /* return period count */
}
/* interrupt threshold not reached; check if wrapped thru zero */
else if (count >= prev) {
result = count - prev;
}
/* interrupt threshold not reached; count *has* wrapped thru zero */
else {
result = (0xffffffff - prev + 1) + count;
}
return (result);
}
/* else ... */
else {
return (Timer_getCount(obj));
}
}
/*
* ======== Timer_getExpiredCounts ========
*
* This API is used by the TimestampProvider as part of retrieving a timestamp
* using a timer and a tick counter. It returns the expired counts since the
* last serviced timer interrupt.
*
* This API must be called with interrupts disabled; the TimestampProvider
* must disable interrupts while retrieving the tick count and calling this
* API.
*
* The TimestampProvider uses a 32-bit timer and 32-bit tick count to track
* the timestamp. The tick count either comes from the Clock module or is
* stored in the TimestampProvider's module state and incremented by an ISR
* when the timer expires.
*
* For MSP430 we have 16-bit timers, and use a timer compare feature to
* trigger an interrupt upon a specific threshold count being reached. The
* timer counts can rollover (going thru zero), on the way to reaching the
* next threshold. We need to accommodate this rollover as part of
* determining expired counts.
*
* We also need to handle the case where there is a large period value used
* for the timer, and the timer is ticking at a fast rate (e.g., the CPU
* rate, via an SMCLK selection). For this case, it is possible that
* interrupts are disabled before the timer reaches threshold, and then the
* timer reaches the threshold count and asserts an interrupt, and then
* continues to count upwards before it is read in this routine. If the
* timer rolled past zero, then we need to know that there is an interrupt
* pending, otherwise we'd report a low count, versus the period plus
* that low count.
*
* To be sure to catch the interrupt, we sample the interrupt flag, read
* the count, and then sample the interrupt flag again:
*
* intrFlag1
* count
* intrFlag2
*
* If intrFlag1 is set, then we know we've reached the period count, and
* need to add it to the reported counts. If intrFlag2 is set, but
* intrFlag1 wasn't, we know the timer just reached threshold, and simply
* report the period count.
*
* If neither interrupt flag is set, we can then compute the expired counts by
* comparing the count to the previous interrupt threshold (saved in the
* timer object). If the current count is greater than or equal to the
* previous threshold value, then we know there has been no counter rollover,
* and the expired counts is simply:
*
* result = count - prevThresh
*
* If the current count is less than the previous threshold, then we know a
* counter rollover has occurred since the last ISR. In this case, the
* expired counts has to include those between the previous threshold and
* zero, plus any counts after rolling past zero:
*
* result = (0 - prevTresh) + count
*
* Similar logic to compare the current count to previous threshold can
* be used for the case where we know intrFlag1 has been set, and we
* need to figure the counts to be added to the period counts.
*
*/
UInt32 Timer_getExpiredCounts(Timer_Object *obj)
{
ti_catalog_msp430_peripherals_timers_TimerRegs *timer;
UInt32 result32;
UInt32 count32;
UInt32 thresh32;
UInt32 period32;
UInt32 prev32;
Bool intrFlag1;
Bool intrFlag2;
timer = (ti_catalog_msp430_peripherals_timers_TimerRegs *)
Timer_module->device[obj->id].baseAddr;
intrFlag1 = timer->cctl_0 & TIMER_COMPARE_INTR_PENDING;
count32 = Timer_getCount(obj) & 0xffff;
intrFlag2 = timer->cctl_0 & TIMER_COMPARE_INTR_PENDING;
prev32 = obj->prevThreshold & 0xffff;
/* interrupt pending before read count? */
if (intrFlag1) {
thresh32 = timer->cc_compare_0 & 0xffff; /* threshold for interrupt */
period32 = Timer_getPeriod(obj) & 0xffff; /* period count */
/* threshold reached; no wrap thru zero yet */
if (count32 >= thresh32) {
result32 = (count32 - thresh32) + period32;
}
/* threshold reached; count has wrapped thru zero */
else {
result32 = (0x10000 - thresh32) + count32 + period32;
}
}
/* new interrupt now pending, when wasn't before read the count */
else if (intrFlag2) {
result32 = Timer_getPeriod(obj) & 0xffff; /* return period count */
}
/* interrupt threshold not reached; check if wrapped thru zero */
else if (count32 >= prev32) {
result32 = count32 - prev32;
}
/* interrupt threshold not reached; count has wrapped thru zero */
else {
result32 = (0x10000 - prev32) + count32;
}
return (result32);
}
/*
* ======== TimestampProvider_get32 ========
* The 32-bit timestamp can be retrieved more efficiently than the 64-bit one,
* so it has a different implementation.
*/
Bits32 TimestampProvider_get32()
{
/*
* If we're sharing the Clock timer, get the timestamp by using the Clock
* tick count.
*/
if (TimestampProvider_useClockTimer) {
UInt key;
UInt32 timestamp;
/*
* Disable interrupts so that the Clock tick count doesn't change if
* the timer expires while we are reading it.
*/
key = Hwi_disable();
/*
* timestamp = (clock ticks) x (tick period) + (current timer count)
* The 'getExpiredCounts' API retrieves the current Timer count and
* also accounts for timer rollover.
*/
timestamp = Clock_getTicks() * Timer_getPeriod(MOD->timer)
+ Timer_getExpiredCounts(MOD->timer);
Hwi_restore(key);
return (timestamp);
}
/* If we have a dedicated timer, just read the timer count. */
else {
return (Timer_getCount(MOD->timer));
}
}
/*
* ======== TimestampProvider_get32 ========
*/
Bits32 TimestampProvider_get32()
{
if (TimestampProvider_useClockTimer) {
UInt key;
UInt32 timestamp;
key = Hwi_disable();
timestamp = Clock_getTicks() * Timer_getPeriod(MOD->timer)
+ Timer_getExpiredCounts(MOD->timer);
Hwi_restore(key);
return (timestamp);
}
else {
return (Timer_getCount(MOD->timer));
}
}
/*
* ======== Timer_getExpiredCounts ========
*/
UInt32 Timer_getExpiredCounts(Timer_Object *obj)
{
UInt key;
UInt32 count1, count2;
Bool itrFlag;
key = Hwi_disable();
count1 = Timer_getCount(obj);
itrFlag = (Hwi_l1Intc.ITR & (0x1 << obj->intNum));
count2 = Timer_getCount(obj);
Hwi_restore(key);
if (count2 < count1 && itrFlag) {
return (count1 + Timer_getPeriod(obj));
}
else {
return (count1) ;
}
}
/*
* ======== TimestampProvider_get64 ========
*/
Void TimestampProvider_get64(Types_Timestamp64 *result)
{
UInt key;
UInt64 timestamp;
key = Hwi_disable();
if (TimestampProvider_useClockTimer) {
timestamp = Clock_getTicks() * Timer_getPeriod(MOD->timer)
+ Timer_getExpiredCounts(MOD->timer);
}
else {
timestamp = ((UInt64)MOD->hi << 32) + Timer_getExpiredCounts(MOD->timer);
}
Hwi_restore(key);
result->hi = timestamp >> 32;
result->lo = timestamp;
}
/*
* ======== Timer_getExpiredCounts ========
*/
UInt32 Timer_getExpiredCounts(Timer_Object *obj)
{
UInt key;
UInt32 count1, count2;
Bool countFlag;
key = Hwi_disable();
count1 = Timer_getCount(obj);
/* Test corresponding Int pending flag */
countFlag = Hwi_nvic.ISPR[0] & (1 << (obj->intNum - 16));
count2 = Timer_getCount(obj);
Hwi_restore(key);
if (count2 < count1 && countFlag) {
return (count1 + Timer_getPeriod(obj));
}
else {
return (count1) ;
}
}
/*
* ======== Timer_getExpiredCounts ========
*/
UInt32 Timer_getExpiredCounts(Timer_Object *obj)
{
UInt key;
UInt32 count1, count2;
Bool countFlag;
extern cregister volatile unsigned int IFR;
key = Hwi_disable();
count1 = Timer_getCount(obj);
/* Test corresponding Int pending flag */
countFlag = IFR & (1 << obj->intNum);
count2 = Timer_getCount(obj);
Hwi_restore(key);
/* CTM Timer */
if (count2 < count1 && countFlag) {
return (count1 + Timer_getPeriod(obj));
}
else {
return (count1) ;
}
}
/*
* ======== TimestampProvider_get64 ========
* This API has different implementations based on whether we're using a
* dedicated timer or sharing the Clock timer.
* If we're sharing the Clock timer, we have to multiply the Clock tick count
* by the Clock tick period. If we have a dedicate timer, the timer period is
* 2^32, so we can just use the MOD->hi tick count as the upper 32-bits of the
* timestamp.
*/
Void TimestampProvider_get64(Types_Timestamp64 *result)
{
UInt key;
/*
* If we're sharing the Clock timer, get the timestamp by using the Clock
* tick count.
*/
if (TimestampProvider_useClockTimer) {
UInt64 timestamp;
/*
* Disable interrupts so that the Clock tick count doesn't change if
* the timer expires while we are reading it.
*/
key = Hwi_disable();
/*
* timestamp = (clock ticks) x (tick period) + (current timer count)
* The 'getExpiredCounts' API retrieves the current Timer count and
* also accounts for timer rollover.
*/
timestamp = (UInt64) Clock_getTicks() * Timer_getPeriod(MOD->timer)
+ Timer_getExpiredCounts(MOD->timer);
Hwi_restore(key);
/*
* Copy the value into the result structure.
*
* The 28x is little endian, so it stores the 16-bit words
* in reverse order. For example, the value
* 0xFEDCBA9876543210
* Is stored as:
* Address Value
* 0x0 0x3210
* 0x1 0x7654
* 0x2 0xBA98
* 0x3 0xFEDC
*
* To retrieve the lower 32 bits, simply cast the value as a UInt32.
* To retrieve the upper 32 bits, cast the address of 'timestamp' as a
* pointer to a UInt32, increment the pointer by 1, then retrieve the
* value at that address.
*/
result->lo = (UInt32) timestamp;
result->hi = *(((UInt32 *) ×tamp) + 1);
}
/* If we have a dedicated timer... */
else {
/* Disable interrupts while reading the tick count and timer value. */
key = Hwi_disable();
/* Use the tick counter as the upper 32-bits. */
result->hi = MOD->hi;
/*
* Get the timer value as the lower 32-bits. This API will also take
* timer rollover into account and add 1 to result->hi if necessary.
*/
Timer_getExpiredCounts64(MOD->timer, result);
Hwi_restore(key);
}
}