Other NXP ProductsのトピックRe: Where is Oscillator Stop (OS) status bit in PCF85263A RTC registers?

Where is Oscillator Stop (OS) status bit in PCF85263A RTC registers?

bobschilken — Sat, 26 Nov 2016 23:35:30 GMT

Where is the Oscillator Stop (OS) status bit in PCF85263A RealTimeClock? The Data Sheet talks at length about the bit, but I cannot find it in the control registers. Access to bit is critical to insure the oscillator has not been interrupted - even for a moment. My design uses super capacitor for backup (and internal switch), but backup voltage can go too low for oscillator to keep functioning. Attached are two relevant pages of data sheet.

Re: Where is Oscillator Stop (OS) status bit in PCF85263A RTC registers?

TomasVaverka — Tue, 29 Nov 2016 19:44:10 GMT

Hi Bob,

It is a bit confusing, but the OS bit is bit 7 in the Seconds Register (01h):

Best regards,

Tomas

Re: Where is Oscillator Stop (OS) status bit in PCF85263A RTC registers?

bobschilken — Tue, 29 Nov 2016 20:25:26 GMT

Thank you! Appreciate the quick response. Maybe you can recommend adding the bolded words to the text right above Figure 9 in the data sheet.

"The status bit remains set until cleared by writing a 0 to bit 7 of register 0x01 command (see Figure 9). If the bit cannot be cleared, then the oscillator is not running. This method can be used to monitor the
oscillator and to determine if the supply voltage has reduced to the point where oscillation
fails."

The rest of the data sheet is very well written. My compliments!