WRTB1
XX
wrtb1xx_g_en_105
22/42
6.1. Computer start up and shut down
Router is turned on after connection of power supply to Vcc and GND terminals
and activation by SB signal.
6.1.1
SB input is used
In terms of data consistence, the unit's start-up is not critical and can be
realized either by coincident connecting of power supply voltage to Vcc and SB
terminals, or by connecting the voltage first to Vcc terminal and then to SB, or
vice versa. Nevertheless, when starting up, an incorrect progress is not
possible.
To prevent data damage the unit must be shut down only by SB terminal.
First, it’s necessary to disconnect the supply voltage from SB terminal, thereby
is initiated a correct process of systemic termination of application and
operating system run. Only after compl
etion of operating system run and unit’s
shut down, the supply voltage can be disconnected from terminal Vcc, or
voltage can be left connected to Vcc terminal permanently.
Voltage waveforms during correct and incorrect switching ON are shown on
following figures.
Vcc
… External power supply
SB
… Voltage on SB pin
HW
… Unit power supply
APP
… Application running / not running
ton
… Time between power-on and application start-up
toff
… Time between deactivation of SB and router power-off
Correct turning on process is ensured by device construction. Correct shut
down process is when the application turns off during
toff1.
Vcc
SB
HW
ton
toff1
t
APP
Fig. 7 - Correct start up and shut down
Power ON
Power OFF
Start up and
shut down
progressions