User Manual
Table Of Contents
- 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 / Preliminary
s
XT55/56_hd_v02.96 Page 66 of 125 18.08.2005
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)