AS3932 データシートの表示（PDF） - austriamicrosystems AG
部品番号
コンポーネント説明
メーカー
AS3932 Datasheet PDF : 33 Pages
| |||
AS3932
Data Sheet - Detailed Description
Most wakeup receivers have to deal with environments that can rapidly change. By periodically monitoring the number of false wakeup events it
is possible to adapt the system setup to the actual characteristics of the environment and enables a better use of the full flexibility of AS3932.
Note: If the Manchester decoder is enabled, the false wakeup register is not able anymore to store the false wakeup events.
Figure 21. Concept of the False Wakeup Register together with the system
Frequency Detector
Wakeup
Level1
Pattern Correlator
Wakeup
Level2
WAKE
Register Setup
Unsuccessful
pattern
correlation
False wakeup
register
READ FALSE WAKEUP REGISTER
Microcontroller
8.9 Real Time Clock (RTC)
The RTC can be based on a crystal oscillator (R1<0>=1), the internal RC-oscillator (R1<0>=0), or an external clock source (R1<0>=1). The
crystal oscillator has higher precision of the frequency with higher current consumption and needs three external components (crystal plus two
capacitors). The RC-oscillator is completely integrated and can be calibrated if a reference signal is available for a very short time to improve the
frequency accuracy. The calibration gets started with the trim_osc direct command. Since no non-volatile memory is available on the chip, the
calibration must be done every time after battery replacement. Since the RTC defines the time base of the frequency detection, the selected
frequency (frequency of the crystal oscillator or the reference frequency used for calibration of the RC oscillator) should be about one forth of the
carrier frequency:
FRTC ~ FCAR * 0.25
(EQ 1)
Where: FCAR is the carrier frequency and FRTC is the RTC frequency
The third option for the RTC is the use of an external clock source, which must be applied directly to the XIN pin (XOUT floating).
www.austriamicrosystems.com/AS3932
Revision 1.2
26 - 33
Share Link: 