Metrologic Instruments IS4921 - Manual (Page 27)

21
Sleep Mode
The engine is sleeping, but is fully powered. The CPU is in sleep mode. The image sensor is in standby
mode, the wakeup from the Sleep Mode requires the image sensor reprogramming (which is done
automatically in the engine software).
PWRDWN Pin State: De-asserted (LOW).
Transition to Sleep Mode:
• The engine is turned to Sleep Mode from Idle Mode upon the expiration of the “sleep” timeout, which is
set to one second by default. The “sleep” timeout is restarted every time the engine enters the Idle
Mode.
• The engine can be turned to Sleep Mode from Operating Mode or Idle Mode immediately upon the
reception of a special single-byte serial command from the host. The byte value is configurable.
Power Down Mode (TTL RS232 Only)
The power of the engine is turned off.
PWRDWN Pin State: Asserted (HIGH).
Transition to Power Down Mode:
• The engine is turned to Power Down Mode from Sleep Mode upon the expiration of the “power-down”
timeout, which is set to 10 minutes by default. The “power-down” timeout is restarted every time the
engine enters the Sleep Mode.
• The engine can be turned to Power Down Mode immediately upon the reception of a special single-
byte serial command from the host. The byte value is configurable.
The engine can wake up from Power Down Mode and reboot:
• Upon reception of the nTrig or nWake signals.
Suspend Mode (USB Only)
The engine is in its lowest power consumption state.
PWRDWN Pin State: Asserted (HIGH).
Transition to Suspend Mode:
• The engine is turned to Suspend Mode upon receiving the USB Suspend signal from the USB host.
• The engine can be turned to Suspend Mode any time (by the USB host).
The engine can wake up from Suspend Mode and reboot:
• Upon receiving the Resume signal from the USB host.