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
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XT55/56_hd_v02.96 Page 74 of 125 18.08.2005
4.3.1 Trickle Power Mode
The default mode of XT55/56 GPS part is continuous mode, but the user can set the
XT55/56 GPS part into the Trickle Power mode using the input command message. The
XT55/56 GPS part enters the Trickle Power mode corresponding to Figure 27 (800ms OFF
time and 200ms ON time) as soon as valid GPS data are available. As a result the average
power consumption is reduced by approximately 80 % (approximately 150mW). The settings
for the Trickle Power mode can be modified by using the SiRFstar demo software. For
example if the XT55/56 GPS part is configured to enter the OnTime mode each 10s for a
duration of 200ms the average power consumption can be reduced up to approx. 95%
(approx. 15mW, ca. 4.8mA at Vcc=3.3V). For more details refer to [1].
Figure 27: Example for current in Trickle Power mode