User's Manual

Boomer II User Manual & Integrator’s Guide _________________________________________________Installation
BM210012WT37 49 Copyright Wavenet Technology © November 2003
Power Down Sequence
The host/terminal may request the modem to turn OFF by de-asserting
the HOSTPWR _ON or by sending a specific NCL command across
the serial interface. For the modem to turn OFF after an NCL request
the HOSTPWR_ON signal must be de-asserted.
Warning: The power supply rail must be maintained during a power
down sequence or else memory may be corrupted.
The soft shutdown process starts when the HOSTPWR_ON control
line is de-asserted. The shutdown process consists of the modem first
de-registering from the network and de-asserting the DCD line. Next, it
saves the modem configuration and network channel information. The
modem then de-asserts the DSR line, signalling the modem is no longer
in a ready state. This process can take a few seconds to complete.
At this point, the host/terminal can remove the power from the modem
and still maintain most of the modem settings and last registered
network channel. The modem can be left with power applied and
HOSTPWR_ON de-asserted.
The reset line HCRESET can be asserted at this time in preparation for
the next power-up sequence. This is optional and is intended for
rebooting the modem only. Resetting the modem causes a cold start
and flushes the saved modem settings.
The following diagram shows the sequence for these actions.
Power-Down Timing Diagram
Note: DSR and DCD are active low signals.
HOSTPWR_ON
DCD
DSR
Modem internal power control
Modem Internal Power
1
2
3
4
Modem software is
Operatio
nal
Network Deregistration
RF Protocol Requirement