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CompactFlash Memory Card Product Manual
command is skipped for the first 16K writes.
When the cycle count (hot count) of a sector
exceeds 16K, the system controller automatically
reverts to a full write, including the final margin
verify. Since the erase is not required in this case,
a write to a pre-erased sector with a hot count of
over 16K is still faster than to a sector that has
not been pre-erased.
command can be used to determine the "hot count"
of a sector.
1.8.6
Automatic Sleep Mode
A unique feature of the SanDisk CompactFlash
Memory Card (and other SanDisk products) is
automatic entrance and exit from sleep mode.
Upon
completion
of
CompactFlash Card will enter the sleep mode to
conserve power if no further commands are
received within 5 msec. The host does not have to
take any action for this to occur. In most systems,
the CompactFlash Memory Card is in sleep mode
except when the host is accessing it, thus
conserving power. Note that the delay from
command completion to entering sleep mode can be
adjusted.
When
the
host
is
CompactFlash Memory Card and it is in sleep
mode, any command issued to the CompactFlash
Card will cause it to exit sleep and respond. The
host does not have to follow the ATA protocol of
issuing a reset first. It may do this if desired, but
it is not needed. By not issuing the reset,
performance is improved through the reduction of
overhead but this must be done only for the
SanDisk products as other ATA products may not
support this feature.
14
The
Translate
Sector
a
command,
the
ready
to
access
the
SanDisk CompactFlash Memory Card Product Manual © 1998 SANDISK CORPORATION
1.8.7
Dynamic Adjustment of Performance
versus Power Consumption
A very unique and valuable feature of the
CompactFlash Memory Card is the ability of the
host to control the power the card consumes. This
allows CompactFlash Cards to work across a
broad
cross
section
compromising performance. For instance, it can
operate in a platform that provides only 32 mA at
3.3 volts average current (of course at reduced
performance) or in a platform that provides 90 mA
at full performance. Please see the Set Features
command for details.
1.8.8
Power Supply Requirements
This is a dual voltage product which means it
will operate at a voltage range of 3.30 volts ± 5%
or 5.00 volts ± 10% (± 5% for industrial versions).
Per the PCMCIA specification section 2.1.1, the
host system must apply 0 volts in order to change a
voltage range. This same procedure of providing 0
volts to the card is required if the host system
applies an input voltage outside the desired
voltage by more than 20%. This means less than
4.0 volts for the 5.00 volt range and less than 2.70
volts for the 3.30 volt range.
of
platforms
without
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