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SiLabs: Correct low power timer setup 

When the requested timeout was not a integer multiple of the
LF clock tick the timestamp was set too short due to rounding,
sometimes causing the ticker event to be missed.
pull/1501/head
jhokajar 2015-11-09 13:07:02 +02:00 committed by Steven Cooreman
parent ab26722b01
commit f6a66ff7e2
1 changed files with 6 additions and 0 deletions
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6
libraries/mbed/targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/lp_ticker.c
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@ -155,6 +155,12 @@ void lp_ticker_set_interrupt(timestamp_t timestamp)
/* map offset to RTC value */
// ticks = offset * RTC frequency div 1000000
timestamp_ticks = ((uint64_t)offset * (LOW_ENERGY_CLOCK_FREQUENCY / RTC_CLOCKDIV_INT)) / 1000000;
// checking the rounding. If timeout is wanted between RTCC ticks, irq should be configured to
// trigger in the latter RTCC-tick. Otherwise ticker-api fails to send timer event to its client
if(((timestamp_ticks * 1000000) / (LOW_ENERGY_CLOCK_FREQUENCY / RTC_CLOCKDIV_INT)) < offset){
timestamp_ticks++;
}
timestamp_ticks += current_ticks;
/* RTCC has 32 bit resolution */