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 54 of 125 18.08.2005
3.6.5.1 Wake-up via /RTS0 and RTS1 (if AT+CFUN=0 or AT+CFUN=9)
During the CYCLIC SLEEP modes 5, 6, 7, and 8, GSM_RTS0 and GSM_RTS1 are
conventionally used for flow control: The assertion of GSM_RTS0 or GSM_RTS1 indicates
that the application is ready to receive data - without waking up the module.
If the module is in CFUN=0 mode the assertion of GSM_RTS0 and GSM_RTS1 serves as a
wake-up event, giving the application the possibility to intentionally terminate power saving. If
the module is in CFUN=9 mode, the assertion of GSM_RTS0 or GSM_RTS1 can be used to
temporarily wake up XT55/56 for the time specified with the AT^SCFG command (default =
2s). In both cases, if GSM_RTS0 or GSM_RTS1 is asserted while AT+CFUN=0 or
AT+CFUN=9 is set, there may be a short delay until the module is able to receive data again.
This delay depends on the current module activities (e.g. paging cycle) and may be up to
60ms. The ability to receive data is signalized by GSM_CTS0 and GSM_CTS1. It is therefore
recommended to enable RTS/CTS flow control, not only in CYCLIC SLEEP mode, but also in
NON-CYCLIC SLEEP mode.