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 64 of 125 17.12.2004
3.12 Control signals
3.12.1 Inputs
Table 17: Input control signals of the GSM part of the XT55/56 module
Signal Pin Pin status Function Remarks
Falling edge Power up XT55/56
Ignition
GSM_IGT
Left open or HiZ No operation
Active low ≥ 100ms (Open
drain/collector driver to GND
required in cellular device
application).
Note: If a charger and a
battery is connected to the
customer application the
GSM_IGT signal must be 1s
minimum.
Low Power down
XT55/56
Emergency
shutdown
GSM_EMERG-
OFF
Left open or HiZ No operation
Active low ≥ 3.2s (Open
drain/collector driver
required in cellular device
application). At the
GSM_EMERGOFF signal
the watchdog signal of the
GSM engine can be traced
(see description in Table
27).
(HiZ = high impedance)