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M14A2A User Manual
2.5.
Control interface (signals)
This section describes the host-to-modem wake-up interface and power-on signal to enable or disable
the control module.
2.5.1.
Power-on Signal
The POWER_ON pad is an input signal used to control whether the module is in the Module Enabled or
Module Disabled state.
Do not toggle the PERST# pin during power-on. This signal has the highest
priority over the wakeup, the alarms signals, and the digital control pins.
The POWER_ON signal is Active Low (VIL for VREF), its voltage level is 1.8V if going to High for Module
Disabled:
POWER_ON is High: Module is OFF
POWER_ON is Low: Module is ON
There are three possible states of the module:
Module Off - VCC is not present.
Module Enabled - VCC is supplied, and the module is enabled.
Module Disabled - VCC is supplied, and the module is disabled.
The state transitions are defined as follows:
When voltage is applied to VCC, the module shall enter the Module Disabled state.
An input to the POWER_ON pad shall trigger the transition from the Module Disabled to the
Module Enabled state.
An input to the POWER_ON pad shall trigger the transition from the Module Enabled to the
Module Disabled state.
Figure 3.
Power ON/OFF timming
In order to prevent the POWER_ON signal in a floating state, it was recommended to pull LOW for
Module Enabled, or pull HIGH to VREF for Module Disabled.
