Integration Manual

TSD-19090601 - R15 Contents Page 35 of 143
Figure 5 describes the TOBY-L3 series modules’ proper normal switch-off sequence started by means of the
PWR_ON input pin, allowing storage of current parameter settings in the module’s non-volatile memory
and a clean network detach, with the following phases
 A low pulse with the appropriate time duration is applied at the PWR_ON input (see TOBY-L3 series
Data Sheet [1], normal graceful switch-off), which is normally set high by an internal pull-up: the module
starts the switch-off routine when the PWR_ON signal is released from the low logical level.
 At the end of the switch-off routine, all the digital pins are tri-stated and all the internal voltage
regulators are turned off, including the generic digital interfaces supply (V_INT).
 Then, the module remains in power-off mode as long as a switch-on event does not occur (i.e. applying
a suitable low level pulse to the PWR_ON input pin), and enters not-powered mode if the supply is
removed from the VCC pins.
VCC
PW R_ON
RESET_N
V_INT
Int ernal Reset
Syst em St at e
BB Pads St at e
OFF
Trist ate / Float ing
ON
Operat ional ->
Trist ate
Operat ional
The module starts
the switch-off routine
VCC
can be removed
Figure 5: Description of TOBY-L3 series power-off sequence, as triggered by PWR_ON input pin
☞ The Internal Reset signal is not available on a module pin, but it is highly recommended to monitor the
V_INT pin to sense the end of the switch-off sequence.
⚠ VCC supply can be removed only after V_INT goes low: an abrupt removal of the VCC supply during
TOBY-L3 series modules normal operations may lead to an unrecoverable faulty state!
☞ The duration of each phase in the TOBY-L3 series modules’ switch-off routines can largely vary
depending on the application / network settings and the concurrent module activities.
1.6.3 Module reset
TOBY-L3 series modules can be properly reset (rebooted) by:
 +CFUN AT command (see the TOBY-L3 series AT Commands Manual [2])