M25P64
SIGNAL DESCRIPTION
Serial Data Output (Q).
This output signal is
used to transfer data serially out of the device.
Data is shifted out on the falling edge of Serial
Clock (C).
Serial Data Input (D).
This input signal is used to
transfer data serially into the device. It receives in-
structions, addresses, and the data to be pro-
grammed. Values are latched on the rising edge of
Serial Clock (C).
Serial Clock (C).
This input signal provides the
timing of the serial interface. Instructions, address-
es, or data present at Serial Data Input (D) are
latched on the rising edge of Serial Clock (C). Data
on Serial Data Output (Q) changes after the falling
edge of Serial Clock (C).
Chip Select (S).
When this input signal is High,
the device is deselected and Serial Data Output
(Q) is at high impedance. Unless an internal Pro-
gram, Erase or Write Status Register cycle is in
progress, the device will be in the Standby Power
mode. Driving Chip Select (S) Low selects the de-
vice, placing it in the Active Power mode.
After Power-up, a falling edge on Chip Select (S)
is required prior to the start of any instruction.
Hold (HOLD).
The Hold (HOLD) signal is used to
pause any serial communications with the device
without deselecting the device.
During the Hold condition, the Serial Data Output
(Q) is high impedance, and Serial Data Input (D)
and Serial Clock (C) are Don’t Care.
To start the Hold condition, the device must be se-
lected, with Chip Select (S) driven Low.
Write Protect (W).
The main purpose of this in-
put signal is to freeze the size of the area of mem-
ory that is protected against program or erase
instructions (as specified by the values in the BP2,
BP1 and BP0 bits of the Status Register).
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