W25Q20BW
8.2.30
Release Power-down / Device ID (ABh)
The Release from Power-down / Device ID instruction is a multi-purpose instruction. It can be used to
release the device from the power-down state, or obtain the devices electronic identification (ID) number.
To release the device from the power-down state, the instruction is issued by driving the /CS pin low,
shifting the instruction code “ABh” and driving /CS high as shown in figure 28a. Release from power-
down will take the time duration of t
RES1
(See AC Characteristics) before the device will resume normal
operation and other instructions are accepted. The /CS pin must remain high during the t
RES1
time
duration.
When used only to obtain the Device ID while not in the power-down state, the instruction is initiated by
driving the /CS pin low and shifting the instruction code “ABh” followed by 3-dummy bytes. The Device ID
bits are then shifted out on the falling edge of CLK with most significant bit (MSB) first as shown in figure
28a. The Device ID values for the W25Q20BW is listed in Manufacturer and Device Identification table.
The Device ID can be read continuously. The instruction is completed by driving /CS high.
When used to release the device from the power-down state and obtain the Device ID, the instruction is
the same as previously described, and shown in figure 28b, except that after /CS is driven high it must
remain high for a time duration of t
RES2
(See AC Characteristics). After this time duration the device will
resume normal operation and other instructions will be accepted. If the Release from Power-down /
Device ID instruction is issued while an Erase, Program or Write cycle is in process (when BUSY equals
1) the instruction is ignored and will not have any effects on the current cycle.
Figure 28a. Release Power-down Instruction Sequence
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Publication Release Date: January 25, 2011
Preliminary - Revision B
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