Rainbow Electronics AT45DB642 User Manual
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AT45DB321E [PRELIMINARY DATASHEET]
8784B–DFLASH–11/2012
Table 1-1.
Pin Configurations
Symbol
Name and Function
Asserted
State
Type
CS
Chip Select: Asserting the CS pin selects the device. When the CS pin is deasserted, the
device will be deselected and normally be placed in the standby mode (not Deep Power-Down
mode) and the output pin (SO) will be in a high-impedance state. When the device is
deselected, data will not be accepted on the input pin (SI).
A high-to-low transition on the CS pin is required to start an operation and a low-to-high
transition is required to end an operation. When ending an internally self-timed operation such
as a program or erase cycle, the device will not enter the standby mode until the completion of
the operation.
Low
Input
SCK
Serial Clock: This pin is used to provide a clock to the device and is used to control the flow of
data to and from the device. Command, address, and input data present on the SI pin is
always latched on the rising edge of SCK, while output data on the SO pin is always clocked
out on the falling edge of SCK.
—
Input
SI
Serial Input: The SI pin is used to shift data into the device. The SI pin is used for all data input
including command and address sequences. Data on the SI pin is always latched on the rising
edge of SCK. Data present on the SI pin will be ignored whenever the device is deselected (CS
is deasserted).
—
Input
SO
Serial Output: The SO pin is used to shift data out from the device. Data on the SO pin is
always clocked out on the falling edge of SCK. The SO pin will be in a high-impedance state
whenever the device is deselected (CS is deasserted).
—
Output
WP
Write Protect: When the WP pin is asserted, all sectors specified for protection by the Sector
Protection Register will be protected against program and erase operations regardless of
whether the Enable Sector Protection command has been issued or not. The WP pin functions
independently of the software controlled protection method. After the WP pin goes low, the
contents of the Sector Protection Register cannot be modified.
If a program or erase command is issued to the device while the WP pin is asserted, the device
will simply ignore the command and perform no operation. The device will return to the idle
state once the CS pin has been deasserted. The Enable Sector Protection command and the
Sector Lockdown command, however, will be recognized by the device when the WP pin is
asserted.
The WP pin is internally pulled-high and may be left floating if hardware controlled protection
will not be used. However, it is recommended that the WP pin also be externally connected to
V
CC
whenever possible.
Low
Input
RESET
Reset: A low state on the reset pin (RESET) will terminate the operation in progress and reset
the internal state machine to an idle state. The device will remain in the reset condition as long
as a low level is present on the RESET pin. Normal operation can resume once the RESET pin
is brought back to a high level.
The device incorporates an internal power-on reset circuit, so there are no restrictions on the
RESET pin during power-on sequences. If this pin and feature is not utilized, then it is
recommended that the RESET pin be driven high externally.
Low
Input
V
CC
Device Power Supply: The V
CC
pin is used to supply the source voltage to the device.
Operations at invalid V
CC
voltages may produce spurious results and should not be attempted.
—
Power
GND
Ground: The ground reference for the power supply. GND should be connected to the system
ground.
—
Ground