Power Saving; Minimum Functionality Mode; Sleep Mode - Quectel M20 Hardware Design

M20 Hardware Design
A 1.6A peak current is allowed for maximum 1ms when charging current is switched on.

3.6 Power saving

There are two methods to drive the module enter low current consumption status. "AT+CFUN" is
used to set module into minimum functionality mode and DTR hardware interface signal can be
used to lead system to enter SLEEP mode.

3.6.1 Minimum functionality mode

Minimum functionality mode reduces the functionality of the module to minimum level, thus
minimizes the current consumption when the slow clocking mode is activated at the same time.
This mode is set with 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 phone both transmitting and receive RF circuits;
If the module is set to minimum functionality by "AT+CFUN=0", the RF function and SIM card
function would be closed. In this case, the serial port is still accessible, but all AT commands
correlative with RF function or SIM card function will not be accessible.
If the module has been set by "AT+CFUN=4", the RF function will be closed, the serial port is
still active. In this case, all AT commands correlative with RF function will not be accessible.
After the module is set by "AT+CFUN=0" or "AT+CFUN=4", it can return to full functionality
by "AT+CFUN=1".
For detailed information about "AT+CFUN", please refer to document [1].

3.6.2 SLEEP mode

The SLEEP mode is disabled in default software configuration. Customer's application can enable
this mode by "AT+QSCLK=1". On the other hand, the default setting is "AT+QSCLK=0" and in
this mode, the module can't enter SLEEP mode.
When "AT+QSCLK=1" is set to the module, customer's application can control the module to
enter or exit from the SLEEP mode through pin DTR. When DTR is set to high level, and there is
no on-air or hardware interrupt such as GPIO interrupt or data on serial port, the module will enter
SLEEP mode automatically. In this mode, the module can still receive voice, SMS or GPRS
paging from network but the serial port is not accessible.
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