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[NRF5]: fix rtc overflow-while-set-timestamp issue #4016

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Merged
merged 2 commits into from
Apr 20, 2017
Merged

[NRF5]: fix rtc overflow-while-set-timestamp issue #4016

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c6ef2f3
[NRF5]: If rtc overflow occurr while setting of timestam then the cco…
nvlsianpu Mar 24, 2017
4f99aa5
[NRF5] us_ticker:
nvlsianpu Apr 3, 2017
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58 changes: 47 additions & 11 deletions targets/TARGET_NORDIC/TARGET_NRF5/us_ticker.c
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@
#include "nrf_drv_common.h"
#include "nrf_drv_config.h"
#include "lp_ticker_api.h"
#include "mbed_critical.h"


//------------------------------------------------------------------------------
Expand All @@ -52,12 +53,25 @@
bool m_common_rtc_enabled = false;
uint32_t volatile m_common_rtc_overflows = 0;

__STATIC_INLINE void rtc_ovf_event_check(void)
{
if (nrf_rtc_event_pending(COMMON_RTC_INSTANCE, NRF_RTC_EVENT_OVERFLOW)) {
nrf_rtc_event_clear(COMMON_RTC_INSTANCE, NRF_RTC_EVENT_OVERFLOW);
// Don't disable this event. It shall occur periodically.

++m_common_rtc_overflows;
}
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I'd extract the above block to some static function, e.g. check_overflow, since the same code needs to be executed in two places.

}

#if defined(TARGET_MCU_NRF51822)
void common_rtc_irq_handler(void)
#else
void COMMON_RTC_IRQ_HANDLER(void)
#endif
{

rtc_ovf_event_check();

if (nrf_rtc_event_pending(COMMON_RTC_INSTANCE, US_TICKER_EVENT)) {
us_ticker_irq_handler();
}
Expand All @@ -69,12 +83,6 @@ void COMMON_RTC_IRQ_HANDLER(void)
}
#endif

if (nrf_rtc_event_pending(COMMON_RTC_INSTANCE, NRF_RTC_EVENT_OVERFLOW)) {
nrf_rtc_event_clear(COMMON_RTC_INSTANCE, NRF_RTC_EVENT_OVERFLOW);
// Don't disable this event. It shall occur periodically.

++m_common_rtc_overflows;
}
}

#if (defined (__ICCARM__)) && defined(TARGET_MCU_NRF51822)//IAR
Expand Down Expand Up @@ -142,13 +150,37 @@ void common_rtc_init(void)
m_common_rtc_enabled = true;
}

__STATIC_INLINE void rtc_ovf_event_safe_check(void)
{
core_util_critical_section_enter();

rtc_ovf_event_check();

core_util_critical_section_exit();
}


uint32_t common_rtc_32bit_ticks_get(void)
{
uint32_t ticks = nrf_rtc_counter_get(COMMON_RTC_INSTANCE);
// The counter used for time measurements is less than 32 bit wide,
// so its value is complemented with the number of registered overflows
// of the counter.
ticks += (m_common_rtc_overflows << RTC_COUNTER_BITS);
uint32_t ticks;
uint32_t prev_overflows;

do {
prev_overflows = m_common_rtc_overflows;

ticks = nrf_rtc_counter_get(COMMON_RTC_INSTANCE);
// The counter used for time measurements is less than 32 bit wide,
// so its value is complemented with the number of registered overflows
// of the counter.
ticks += (m_common_rtc_overflows << RTC_COUNTER_BITS);

// Check in case that OVF occurred during execution of a RTC handler (apply if call was from RTC handler)
// m_common_rtc_overflows might been updated in this call.
rtc_ovf_event_safe_check();

// If call was made from a low priority level m_common_rtc_overflows might have been updated in RTC handler.
} while (m_common_rtc_overflows != prev_overflows);

return ticks;
}

Expand Down Expand Up @@ -185,6 +217,8 @@ void common_rtc_set_interrupt(uint32_t us_timestamp, uint32_t cc_channel,
uint32_t compare_value =
(uint32_t)CEIL_DIV((timestamp64) * RTC_INPUT_FREQ, 1000000);


core_util_critical_section_enter();
// The COMPARE event occurs when the value in compare register is N and
// the counter value changes from N-1 to N. Therefore, the minimal safe
// difference between the compare value to be set and the current counter
Expand All @@ -197,6 +231,8 @@ void common_rtc_set_interrupt(uint32_t us_timestamp, uint32_t cc_channel,

nrf_rtc_cc_set(COMMON_RTC_INSTANCE, cc_channel, RTC_WRAP(compare_value));
nrf_rtc_event_enable(COMMON_RTC_INSTANCE, int_mask);

core_util_critical_section_exit();
}
//------------------------------------------------------------------------------

Expand Down