Micron M25P40 Serial Flash Embedded Memory
READ IDENTIFICATION
READ IDENTIFICATION
The READ IDENTIFICATION command reads the following device identification data:
• Manufacturer identification (1 byte): This is assigned by JEDEC.
• Device identification (2 bytes): This is assigned by device manufacturer; the first byte
indicates memory type and the second byte indicates device memory capacity.
• A Unique ID code (UID) (17 bytes,16 available upon customer request): The first byte
contains length of data to follow; the remaining 16 bytes contain optional Customized
Factory Data (CFD) content.
Table 6: READ IDENTIFICATION Data Out Sequence
Device Identification
UID
Manufacturer
Identification
Memory Type
Memory Capacity
CFD Length
CFD Content
20h
20h
13h
10h
16 bytes
1. The CFD bytes are read-only and can be programmed with customer data upon demand.
If customers do not make requests, the devices are shipped with all the CFD bytes pro-
grammed to zero.
Note:
A READ IDENTIFICATION command is not decoded while an ERASE or PROGRAM cy-
cle is in progress and has no effect on a cycle in progress. The READ IDENTIFICATION
command must not be issued while the device is in DEEP POWER-DOWN mode.
The device is first selected by driving chip select (S#) LOW. Then the 8-bit command
code is shifted in and content is shifted out on serial data output (DQ1) as follows: the
24-bit device identification that is stored in the memory, the 8-bit CFD length, followed
by 16 bytes of CFD content. Each bit is shifted out during the falling edge of serial clock
(C).
The READ IDENTIFICATION command is terminated by driving S# HIGH at any time
during data output. When S# is driven HIGH, the device is put in the STANDBY POWER
mode and waits to be selected so that it can receive, decode, and execute commands.
PDF: 09005aef8456654f
m25p40.pdf - Rev. Y 8/12 EN
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