User's Manual
Table Of Contents
- Document History
- Introduction
- Product Concept
- Application Interface
- Operating Modes
- Power Supply
- Power Up / Power Down Scenarios
- Automatic GPRS Multislot Class Change
- Charging Control
- Summary of State Transitions (Except SLEEP Mode)
- RTC Backup
- SIM Interface
- Serial Interface ASC0
- Serial Interface ASC1
- USB Interface
- I2C Interface
- Audio Interfaces
- Control Signals
- Antenna Interface
- Electrical, Reliability and Radio Characteristics
- Mechanics
- Sample Application
- Reference Approval
- Appendix
TC63 Hardware Interface Description
Strictly confidential / Draft
s
TC63_HD_V00.432 Page 42 of 97 11.05.2005
3.7 RTC Backup
The internal Real Time Clock of TC63 is supplied from a separate voltage regulator in the
analog controller which is also active when TC63 is in POWER DOWN status. An alarm
function is provided that allows to wake up TC63 to Airplane mode without logging on to the
GSM network.
In addition, you can use the VDDLP pin on the board-to-board connector to backup the RTC
from an external capacitor or a battery (rechargeable or non-chargeable). The capacitor is
charged by the BATT+ line of TC63. If the voltage supply at BATT+ is disconnected the RTC
can be powered by the capacitor. The size of the capacitor determines the duration of
buffering when no voltage is applied to TC63, i.e. the larger the capacitor the longer TC63
will save the date and time.
A serial 1k resistor placed on the board next to VDDLP limits the charge current of an
empty capacitor or battery.
The following figures show various sample configurations. Please refer to Table 17 for the
parameters required.
Baseband
processor
RTC
PSU
+
BATT+
1k
B2B
VDDLP
Figure 9: RTC supply from capacitor
RTC
+
BATT+
1k
B2B
VDDLP
Baseband
processor
PSU
Figure 10: RTC supply from rechargeable battery
RTC
+
+
BATT+
1k
VDDLP
B2B
Baseband
processor
PSU
Figure 11: RTC supply from non-chargeable battery