User's Manual

GSM/GPRS/GNSS Module Series
MC20 Hardware Design
MC20_Hardware_Design Confidential / Released 33 / 95
Based on system requirements, there are several actions to drive the GSM part to enter into low current
consumption status. For example, AT+CFUN can be used to set the part into minimum functionality mode,
and DTR hardware interface signal can be used to lead the system to Sleep Mode.
3.4.1.1. Minimum Functionality Mode
Minimum functionality mode reduces the functionality of the GSM part to a minimum level. The
consumption of the current can be minimized when the slow clocking mode is activated at the same time.
The mode is set via the AT+CFUN command which provides the choice of the functionality levels
<fun>=0, 1, 4.
 0: minimum functionality
 1: full functionality (default)
 4: disable from both transmitting and receiving RF signals
If the GSM part is set to minimum functionality by AT+CFUN=0, the RF function and SIM card function
would be disabled. In this case, the UART port is still accessible, but all AT commands related with RF
function or SIM card function will be unavailable.
If the GSM part is set by the command AT+CFUN=4, the RF function will be disabled, but the UART port
is still active. In this case, all AT commands related with RF function will be unavailable.
GPRS IDLE
The GSM part is not registered on GPRS network. It is not
reachable through GPRS channel.
GPRS
STANDBY
The GSM part is registered on GPRS network, but no GPRS
PDP context is active. The SGSN knows the Routing Area
where the module is located at.
GPRS READY
The PDP context is active, but no data transfer is ongoing. The
GSM part is ready to receive or send GPRS data. The SGSN
knows the cell where the module is located at.
GPRS DATA
There is GPRS data in transfer. In this mode, power
consumption is decided by the PCL, working RF band and
GPRS multi-slot configuration.
POWER DOWN
Normal shutdown by sending the AT+QPOWD=1 command or using the
PWRKEY pin. The power management ASIC disconnects the power supply from
the base band part of the GSM part. Software is not active. The UART interfaces
are not accessible. Operating voltage (connected to VBAT) remains applied.
Minimum
Functionality Mode
(without removing
power supply)
AT+CFUN command can set the GSM part to a minimum functionality mode
without removing the power supply. In this case, the RF part of the GSM part will
not work or the SIM card will not be accessible, or both RF part and SIM card will
be disabled; but the UART port is still accessible. The power consumption in this
case is very low.