Symbol SE 923, Integration Manual

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SE-923 Scan Engine Integration Guide
WAKEUP
Description: Wakeup decoder after it’s been put into low power
operation
If the decoder is in low power mode, sending the single character, NULL (0x00) wakes up the
decoder. This character is only needed when hardware handshaking is not being used or has
been bypassed. (See
Power Management on page 1-4.)
Host Requirements
Once the WAKEUP character has been sent, the host must wait at least 10 msec, but less than
1 second before sending additional data, since the decoder is required to wait 1 second after
waking up before going back to sleep automatically (if low power mode is enabled).
Decoder Requirements
The decoder must not go back into low power mode for at least 1 second after waking up.
Note: The mechanism to wake up a decoder in this manner also works if
characters other than WAKEUP are sent to the decoder. There is,
however, no guarantee that these commands are interpreted correctly
upon power-up. Therefore, it is not recommended that characters
other than WAKEUP be used to awaken the decoder.
The WAKEUP character has no effect if sent when the scanner is awake. If the host is unsure
of the scanner state, it should send the wakeup character anytime it wants to communicate
with the scanner.
SSI Transactions
General data transactions
ACK/NAK Handshaking
ACK/NAK handshaking may be enabled or disabled. If this parameter is set, all packeted
messages must have a CMD_ACK or CMD_NAK response, unless the command description
states otherwise. This parameter is enabled by default. This handshaking should remain
enabled to provide feedback to the host. Raw decode data and WAKEUP do not use ACK/
NAK handshaking since they are not packeted data.