Proprietary and Confidential Information of YAMAR Electronics Ltd.
4.5
Reset and Power-up
The device has internal Power-up reset. It takes 6mS until a stable operation is achieved from power-
up, or from raising the nReset signal to high.
4.6
Sleep Mode
The device has three operation modes: Normal mode (normal transmitting and receiving), Sleep mode
(power saving mode), and Standby mode (after waking up, while pin nSleep is low). Transitions
between the modes are done via dedicated pins, or remotely, due to bus activity.
4.6.1
Entering Sleep mode
Host can move the device into Sleep mode from Normal mode either by a lowering to "0" (falling edge)
pin nSleep or enabling the AutoSleep option (Setting Register 0 bit 4 to “0”). The device enters to Sleep
mode and lowers output pin INH.
When AutoSleep option is enabled the device will enter Sleep mode if there was no reception from the
bus for a period of 8 Sec. EVEN if the device is currently transmitting. The device must receive data
from the bus in order to reset its internal autosleep timer. There are three ways to wakeup the device
from Sleep mode.
4.6.2
Wakeup from pin nSleep
In this case, the host raises pin nSleep. The device then enters Normal mode and raises pin INH. The
device automatically transmits a wakeup message to wakeup all other devices on the bus. While
transmitting this wakeup message to the bus, the device lowers pin HDO. After the transmission is
complete the device raises pin HDO (can be used to signal/interrupt the host). After the transmission is
completed and pin nSleep is high, the device enters Normal mode. See Figure 4.5 for signals
description.
T5
nSleep
INH
Wakeup Message
DC-BUS
Normal
Standby
HDO
T7
Figure 4.5 - Wakeup from nSleep
Wakeup from pin Wake
4.6.3
In this case, a transition on pin Wake (caused by an external switch of the application) is used to wake
the device. The device then enters Standby mode, raises pin INH, and transmits a wakeup message to
the bus. While transmitting the wakeup message to the bus, the device lowers pin HDO. After the
transmission is complete the device raises pin HDO (can be used to signal/interrupt the host). After the
transmission is completed and pin nSleep is high, the device enters Normal mode. The host has to raise
the nSleep pin (otherwise the device will remain in Standby mode).
@ 2007 Yamar Electronics Ltd.
10
DS-SIG40 R1.8
YAMAR [ YAMAR ELECTRONICS LTD. ]
