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introduce FUZZY_RTC_TICKS for comparsions

pull/932/head
Rohit Grover 2015-02-25 14:46:06 +00:00 committed by Rohit Grover
parent 5cf0f29cfc
commit 7c0e814bd4
1 changed files with 10 additions and 2 deletions
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12
libraries/mbed/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/us_ticker.c
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@ -40,6 +40,14 @@
* timeout handlers). */
#define MAX_RTC_TASKS_DELAY 47 /**< Maximum delay until an RTC task is executed. */
#define FUZZY_RTC_TICKS 2 /* RTC COMPARE occurs when a CC register is N and the RTC
* COUNTER value transitions from N-1 to N. If we're trying to
* setup a callback for a time which will arrive very shortly,
* there are limits to how short the callback interval may be for us
* to rely upon the RTC Compare trigger. If the COUNTER is N,
* writing N+2 to a CC register is guaranteed to trigger a COMPARE
* event at N+2. */
#define RTC_UNITS_TO_MICROSECONDS(RTC_UNITS) (((RTC_UNITS) * (uint64_t)1000000) / RTC_CLOCK_FREQ);
#define MICROSECONDS_TO_RTC_UNITS(MICROS) ((((uint64_t)(MICROS) * RTC_CLOCK_FREQ) + 999999) / 1000000)
@ -194,8 +202,8 @@ void us_ticker_set_interrupt(timestamp_t timestamp)
uint32_t newCallbackTime = MICROSECONDS_TO_RTC_UNITS(timestamp);
/* Check for callbacks which are immediately pending. */
if ((int)(newCallbackTime - rtc1_getCounter()) <= 0) {
/* Check for callbacks which are immediately (or will *very* shortly become) pending. */
if ((int)(newCallbackTime - rtc1_getCounter()) <= (int)FUZZY_RTC_TICKS) {
INVOKE_CALLBACK();
return;
}