Real Time Clock (Rtc) Circuit; Rtc Initialization; Rtc Functional Block Diagram; Table 15: Frequency Characteristics Of The Table 16: Cm52 Audios - Wavecom CM52 Integrator's Manual

Parameter
Supply Voltage Reference
Output Current
Application Load
Rise Time
Fall Time
2.5

Real Time Clock (RTC) Circuit

The real time clock is a feature provided by the CM52 that allows the Wireless CPU
wakeup for a definable number of cycles, as configured by the host application. This feature is an
optional hardware feature. Please refer to the CM52 Software User's Guide and AT Command
Manual for more details about usage scenarios and programming this feature.
The following table defines the Frequency Characteristics of the RTC:
Item
Frequency
precision
Frequency /
voltage
characteristics
Frequency /
temperature
characteristics
Aging
(*1) precision gap per month: 1 minutes (excluding offset value)

RTC Initialization

2.5.1
When power is first applied to the RTC via the VRTC pin of the system connector it is necessary to
allow the CM52 to initialize the RTC. In order to initialize the RTC the CM52 must be powered up
while power is applied to the RTC. Once the Restart message is received the CM52 can be
shutdown via the normal procedures. If the supply to the VRTC input is interrupted then the CM52
must be allowed to power up to initialize the RTC again.

RTC Functional Block Diagram

2.5.2
The purpose of this section is to provide an overview of the Real Time Clock feature functional
block and interconnects that are shared with the application.
CM52 Integrators' Manual
WI_DEV_CM52_UGD_001-001
Page 26 of 53
Minimum
2.45
10
Table 14: VREF Supply Details
Symbol Condition
Δf / f Ta = +25 °C,
VDD = 3.0 V
f / V Ta = +25 °C,
VDD = 2.0 V to 5.0 V
Top Ta = -20 °C to +70 °C,
VDD = 3.0 V;
+25 °C reference
fa Ta = +25 °C,
VDD = 3.0V,
first year
Table 15: Frequency characteristics of the RTC
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CM52 Integrators' Manual
Typical Maximum
2.9 3.1
1000
100
3300
0.8
Rating Unit
5 ± 23 (*1) X 10-6
± 2 Max. X 10 -6 / V
+10 / -120 X 10 -6
± 5 Max. X 10 -6 / year
Units
V
uA
KΩ
us
ms
to sleep and
®