Serial I/O - Motorola Symbol MS4404 Integration Manual

1 - 6 Symbol MS4404/MS4407 Integration Guide
Table 1-1 describes how to put the Symbol MS4404 into Low Power mode;
Completely removing power from the Symbol MS4404 is not recommended; this should not be necessary as in Low
Power mode the Symbol MS4404 consume very little power (see
Placing the Symbol MS4404 into Low Power Mode
Table 1-1
Action
Set the Power Mode parameter to Low
Power (see Power Mode on page
Send the serial SLEEP command
(see the Simple Serial Interface (SSI)
Programmer Guide).
Note: All Wake Up signals (see
Symbol MS4404 is awakened, at least 1 second (programmable time) must elapse before it
re-enters Low Power mode.
Waking Up the Symbol MS4404
Table 1-2
Signal
AIM/WKUP*
TRIG*
CTS*
RXD
When the Symbol MS4404 is awakened, it remains awake for at least 1 second (programmable time) before
re-entering Low Power mode; the host must perform its first action within this time period.

Serial I/O

Simple Serial Interface (SSI) Protocol is a half-duplex asynchronous serial interface with two hardware handshaking
lines. The four SSI-specific interface signals are:
•
TXD - Transmitted Data
•
RXD - Received Data
•
RTS* - Request to Send
• CTS* - Clear to Send
Signal names with the "*" modifier are asserted when at the positive logic 0 state (active low).
Signal names without the "*" modifier are asserted when at the positive logic 1 state (active high).
The TXD line transmits asynchronous serial data from the Symbol MS440X to the host.
The RXD line is used by the Symbol MS440X to receive asynchronous serial data from the host. The SSI protocol
does not support full-duplex data transfers; data is either transmitted or received by the Symbol MS440X, but never
both simultaneously.
The RTS* and CTS* signals help coordinate data transfers between the Symbol MS440X and the host.
The Symbol MS4404 enters Low Power mode
6-8). automatically whenever possible.
The Symbol MS4404 enters Low Power mode only
once, as soon as possible.
Table 1-2) must be inactive to enter Low Power mode. Once the
State to Wake Up
Low
Low
Low
Send 0x00
Table 1-2 describes how to awaken it.
Table 1-1).
Behavior