Power Management - Symbol SE 923 Integration Manual

SE-923 Scan Engine Integration Guide
its internal RAM. If a fault is found, the decoder copies factory default values into RAM and
the memory. The decoder does not correct the fault unless requested by the host.

Power Management

The SE-923 has two power modes:
Continuous Power
•
Low Power.
•
In Continuous Power mode, the SE-923 always waits for a trigger pull or serial
communication.
In Low Power mode, the SE-923 draws less current than when in Continuous Power mode,
making it more suitable for battery powered applications. The Power Mode parameter (page
12) puts the SE-923 into Low Power mode whenever possible. The SE-923 can also be put
into Low Power mode by use of the SLEEP command (see SLEEP on page 6-31).
The SE-923 must be awakened from the Low Power mode before performing any functions.
Whenever the SE-923 is in the Low Power mode, the PWRDWN signal is asserted. This
signal is used by the host to remove power from the SE-923. Removing power without
using this signal is not recommended since the PWRDWN signal is the only way to know
if the decoder is not transmitting, receiving, decoding, or writing data to non-volatile
memory. Table 1-1 shows how to put the SE-923 into Low Power mode. Table 1-2 shows
how to awaken it.
Action
Set the Power Mode
parameter to Low Power
Send the serial SLEEP
command
Note:
All Wake Up signals (see Table 1-2) must be inactive in order to enter Low Power mode. Once the
SE-923 is awakened, at least 1 second must elapse before it re-enters Low Power mode.
1-4
Table 1-1. SE-923 into Low Power Mode
The SE-923 enters Low Power mode automatically whenever
possible.
The SE-923 enters Low Power mode only once, as soon as
possible.
Behavior