User's Manual
Table Of Contents
- Document history
- Introduction
- Product concept
- Application Interface
- Antenna interface
- Electrical, reliability and radio characteristics
- Mechanics
- Reference Approval
- Design example
- List of parts and accessories
MC55/56 Hardware Interface Description
Confidential / Preliminary
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MC55/56_hd_v03.00 Page 31 of 104 16.08.2005
In Alarm mode only a limited number of AT commands is available. For further instructions
refer to the AT Command Set.
Table 5: AT commands available in Alarm mode
AT command Use
AT+CALA Set alarm time
AT+CCLK Set date and time of RTC
AT^SBC In Alarm mode, you can only query the present current consumption and check
whether or not a charger is connected. The battery capacity is returned as 0,
regardless of the actual voltage (since the values measured directly on the cell are
not delivered to the module).
AT^SCTM Query temperature range, enable/disable URCs to report critical temperature
ranges
AT^SMSO Power down GSM engine
For the GSM engine to change from the Alarm mode to full operation (normal operating
mode) it is necessary to drive the ignition line to ground. This must be implemented in your
host application as described in Chapter 3.3.1.1.
If the charger is connected to the POWER line when MC55/56 is in ALARM mode charging
will start, while MC55/56 stays in ALARM mode. See also Chapter 3.7 which summarizes the
various options of changing the mode of operation.
If your host application uses the SYNC pin to control a status LED as described in Chapter
3.12.2.2, please note that the LED is off while the GSM engine is in Alarm mode.