User Manual
Table Of Contents
- 1. Introduction
- 2. GR47/GR48 Radio Devices
- 3. Abbreviations
- 4. Mechanical Description
- 5. System Connector Interface
- 5.1 Overview
- 5.2 General Electrical and Logical Characteristics
- 5.3 Grounds
- 5.4 VCC - Regulated Power Supply Input
- 5.5 Battery Charging Input (CHG_IN)
- 5.6 Turning the Radio Device ON/OFF and the External Power Signal
- 5.7 Analogue Audio
- 5.8 PCM Digital Audio
- 5.9 Serial Data Interfaces
- 5.10 SIM Card Related Signals
- 5.11 Service/Programming
- 5.12 Buzzer
- 5.13 LED
- 5.14 General Purpose Digital I/O Ports
- 5.15 Extended I/O capabilities
- 5.16 General Purpose Analogue I/O Ports
- 5.17 External I 2C Serial Control Bus
- 5.18 TX_ON - Burst Transmission
- 5.19 Real Time Clock
- 6. Antenna Connector
- 7. Keyboard Interface
- 8. Hints for Integrating the Radio Device
- 9. Embedded Applications
- 10. TCP/IP Stack
- 11. Technical Data
- 12. Declaration of Conformity
- 13. Introduction to the Developer’s Kit
- 14. Using the Developer’s Kit
5. SYSTEM CONNECTOR INTERFACE
50
LZT 123 7589 R1A
In back-up mode, the back-up source must provide enough power for RTC
operation. Refer to the table for the amount of current required.
The following table shows voltage characteristics for both modes.
If the voltage drops below 1.0 V in back-up mode, the RTC will stop
working. The following diagram shows the RTC connections.
Figure 5.13 RTC connections
Parameter Min. Typ. Max. Units
Supply Voltage RTC (normal mode -
charging the capacitor)
1.6 1.8 2.0 V
Supply Voltage RTC (back-up mode -
Capacitor provides the current)
1.0 1.8 2.0 V
Current drawn 5.0 10.0 µA
Backup
supply
VRTC
+
GR47
DGND