User's Manual
Table Of Contents
- Contents
- Figures
- Tables
- Document history
- Introduction
- Product concept
- GSM application interface
- GSM/GPRS operating modes
- Power supply
- Power up / down scenarios
- Automatic GPRS Multislot Class change
- Charging control of the GSM part
- Power saving
- Summary of state transitions (except SLEEP mode)
- RTC backup for GSM part of XT55/56
- Serial interfaces of the XT55/56 GSM part
- Audio interfaces
- SIM interface
- Control signals
- GPS application interface
- GSM and GPS antenna interfaces
- Electrical, reliability and radio characteristics
- Mechanics
- Reference approval
- Example applications
- List of parts and accessories
XT55/56 Hardware Interface Description
Confidential / Released
s
XT55/56_hd_v02.06a Page 122 of 125 17.12.2004
Figure 58 shows a sample application that incorporates an XT55/56 module and an external
µC which controls the entire application.
This µC must provide two asynchronous serial interfaces for controlling the XT55/56. One
serial interface (TXD0, RXD0, CTS0, RTS0) controls the GSM part. The other serial interface
(TXD1, RXD1) controls the GPS part of the XT55/56 module. It is recommended to use an
interrupt input of the external µC for RING0 detection.
If the application uses IP-based data connections (internet access via GPRS or CSD), the
external µC is responsible for handling the IP protocol.
To update the GSM and GPS software the test points (TP) must be used.
Disclaimer
No warranty, either stated or implied, is provided on the sample schematic diagram shown in
Figure 58 and the information detailed in this section. As functionality and compliance with
national regulations depend to a great amount on the used electronic components and the
individual application layout manufacturers are required to ensure adequate design and
operating safeguards for their products using XT55/56 modules.