"*" these signal lines are redefined
during the Ultra DMA protocol to provide special
functions as detailed in the table below. These
lines change from the conventional to special
definitions at the moment the host decides to
allow a DMA burst, if the Ultra DMA transfer
mode was previously chosen via Set Features. The
drive becomes aware of this change upon
assertion of the -DMACK line. These lines revert
back to their original definitions upon the
deassertion of -DMACK at the termination of the
DMA burst.
There are two input pins for +5 Volt power
supply, "+5V Logic" and "+5V
Motor". "+5V Logic" is connected
to the internal logic circuits and "+5V
Motor" is connected to the spindle motor
and motor driver.
It is possible to turn on and off "+5V
Logic" by an external switch circuit to
reduce power consumption to the least possible.
In this mode, a voltage drop out due to the
motor spin up current can be reduced by
connecting "+5V Motor" line into the
system power source directly.
If the above power management option is used,
all signal lines that will be electrically
active in the host system while the hard disk
drive is disconnected from power line shall be
isolated by three-state line drivers. Internal
leakage through ESD protection circuit may pull
down LPUL (least positive up level) of logic
signal below specification.
Use both lines in parallel, for regular hard
disk drive applications.
