SE868-V3 Product User Guide
1VV0301205 r4 – 2016-01-20
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
Page 38 of 76
Mod. 0805 2015-02 Rev.4
9.4.4.
ON-OFF (input) and SYSTEM-ON (output)
The SE868-V3 module has three power states: OFF, RESET, and ON.
The ON state has three substates: HIBERNATE, STANDBY, and RUN.
The OFF state exists when power is removed from the module.
Upon initial application of power, the module enters the RESET state until the internal reset
process is completed. It then transitions (at least briefly) to the ON state.
In the ON state, the module will transition to either the RUN or HIBERNATE substate
depending on the status of the ON-OFF pin.
•
If the ON-OFF pin is high, the module will transition to the RUN substate.
•
If the ON-OFF pin is low, the module will transition to the HIBERNATE substate.
Note
: The ON_OFF pin must not be tied to V18 because it must be brought low, then high to
transition out of a commanded hibernate state.
The module will transition to the RESET state when external reset (nRESET) is pulled low, or
upon internal reset (e.g. supply voltage out of spec). The external nRESET signal takes
precedence over the state of the ON-OFF signal. SYSTEM-ON will be logic low.
While in the ON state, there are three substates, depending upon the status of the ON-OFF pin,
commands or selected power management modes. The three substates are: HIBERNATE,
STANDBY, and RUN.
The module transitions between RUN and STANDBY via TricklePower modes; and between
RUN and HIBERNATE via PushToFix and SiRFaware modes. It can also transition from RUN
to HIBERNATE by de-asserting the ON-OFF signal. The firmware is configured to transition
from HIBERNATE to RUN when data is received on the RX pin. Note that the first character
received is invalid in this case, so the command will not be acted upon.
•
In the RUN substate, the SYSTEM-ON signal will be logic high.
•
In the STANDBY OR HIBERNATE states, SYSTEM-ON will be logic low.
To execute an orderly shutdown, first place the module in the HIBERNATE substate, then
remove power.
Also, see
Section 9.5 Reset.
