LH28F400BVE-TL85 Sharp Electronics, LH28F400BVE-TL85 Datasheet - Page 10

• Manufacturer Part Number: LH28F400BVE-TL85
• Manufacturer: Sharp Electronics

Specifications of LH28F400BVE-TL85

• Cell Type: NOR
• Density: 4Mb
• Interface Type: Parallel
• Boot Type: Top
• Address Bus: 19/18Bit
• Operating Supply Voltage (typ): 3.3/5V
• Operating Temp Range: 0C to 70C
• Package Type: TSOP
• Program/erase Volt (typ): 2.7/3.3/5/12V
• Sync/async: Asynchronous
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (min): 2.7/4.5V
• Operating Supply Voltage (max): 3.6/5.5V
• Word Size: 8/16Bit
• Number Of Words: 512K/256K
• Supply Current: 65mA
• Mounting: Surface Mount
• Pin Count: 48
• Lead Free Status / Rohs Status: Not Compliant

3 BUS OPERATION
The local CPU reads and writes flash memory in-system.
All bus cycles to or from the flash memory conform to
standard microprocessor bus cycles.
3.1 Read
Information can be read from any block, identifier codes
or status register independent of the V
be at either V
The first task is to write the appropriate read mode
command (Read Array, Read Identifier Codes or Read
Status Register) to the CUI. Upon initial device power-up
or after exit from deep power-down mode, the device
automatically resets to read array mode. Six control pins
dictate the data flow in and out of the component: CE#,
OE#, WE#, RP#, WP# and BYTE#. CE# and OE# must be
driven active to obtain data at the outputs. CE# is the
device selection control, and when active enables the
selected memory device. OE# is the data output
(DQ
memory data onto the I/O bus. WE# must be at V
RP# must be at V
cycle.
3.2 Output Disable
With OE# at a logic-high level (V
are disabled. Output pins (DQ
high-impedance state.
3.3 Standby
CE# at a logic-high level (V
standby mode which substantially reduces device power
consumption. DQ
impedance state independent of OE#. If deselected during
0
-DQ
15
) control and when active drives the selected
IH
or V
IH
0
-DQ
HH
or V
.
15
HH
outputs are placed in a high-
. Figure 13, 14 illustrates read
IH
0
-DQ
) places the device in
IH
), the device outputs
15
PP
) are placed in a
voltage. RP# can
IH
and
block erase or word/byte write, the device continues
functioning, and consuming active power until the
operation completes.
3.4 Deep Power-Down
RP# at V
In read modes, RP#-low deselects the memory, places
output drivers in a high-impedance state and turns off all
internal circuits. RP# must be held low for a minimum of
100ns. Time t
down until initial memory access outputs are valid. After
this wake-up interval, normal operation is restored. The
CUI is reset to read array mode and status register is set to
80H.
During block erase or word/byte write modes, RP#-low
will abort the operation. RY/BY# remains low until the
reset operation is complete. Memory contents being
altered are no longer valid; the data may be partially
erased or written. Time t
to logic-high (V
written.
As with any automated device, it is important to assert
RP# during system reset. When the system comes out of
reset, it expects to read from the flash memory. Automated
flash memories provide status information when accessed
during block erase or word/byte write modes. If a CPU
reset occurs with no flash memory reset, proper CPU
initialization may not occur because the flash memory
may be providing status information instead of array data.
SHARP’s flash memories allow proper CPU initialization
following a system reset through the use of the RP# input.
In this application, RP# is controlled by the same RESET#
signal that resets the system CPU.
IL
initiates the deep power-down mode.
PHQV
IH
) before another command can be
is required after return from power-
PHWL
is required after RP# goes
Rev. 1.02