[73] TIMER: Event lost

This anomaly applies to IC Rev. Engineering B, build codes QFAA-BA0, CHAA-AA0.

It was inherited from the previous IC revision Engineering A.

Symptoms

If an event from the peripherals listed below comes within 125 ns of the CPU and all other peripherals going to IDLE, the event flag may not be set and the event would be lost. The effected peripherals are RTC, LPCOMP, GPIO, and WDT. These peripherals are commonly used to wake the system from a low power IDLE state. Loss of events would prevent the wakeup from occurring.

Conditions

Always

Consequences

Lost events.

Workaround

Use the following workaround to prevent some core peripheral services from going to the lowest power mode. This will cause an increase of around 20 µA current in SYSTEM ON IDLE.
 
if (*(volatile uint32_t *)0x4006EC00 == 0) 
{ *(volatile uint32_t *)0x4006EC00 = 0x9375; } 
*(volatile unit32_t *) 0x4006EC14 = 0xC0; 
To turn off this workaround (to save current):
 
if (*(volatile uint32_t *)0x4006EC00 == 0) 
{ *(volatile uint32_t *)0x4006EC00 = 0x9375; } 
*(volatile unit32_t *) 0x4006EC14 = 0x0; 

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