n25q256 Numonyx, n25q256 Datasheet - Page 64

• Manufacturer Part Number: n25q256
• Description: 256-mbit 3 V, Multiple I/o, 4-kbyte Subsector Erase, Xip Enabled, Serial Flash Memory With 108 Mhz Spi Bus Interface
• Manufacturer: Numonyx

Instructions
9.1.1
Table 17.
Table 18.
64/186
20h
Reserved Reserved Reserved
Bit 7
Manufacturer
Identification
Read Identification (RDID)
The Read Identification (RDID) instruction allows to read the device identification data:
The manufacturer identification is assigned by JEDEC, and has the value 20h. The device
identification is assigned by the device manufacturer, and indicates the memory type in the
first byte (BAh), and the memory capacity of the device in the second byte (19h). The UID is
composed by 17 read only bytes, containing the length of the following data in the first byte
(set to 10h), 2 bytes of Extended Device ID (EDID) to identify the specific device
configuration (Top, Bottom or uniform architecture, Hold or Reset functionality), and 14
bytes of the Customized Factory Data (CFD) content. The CFD bytes are factory
programmed.
The CFD bytes are factory programmed with a unique identification number for each single
device. This area can be accessed in read mode only. It is impossible to change the security
number after it has been written by manufacturing.
Any Read Identification (RDID) instruction while an Erase or Program cycle is in progress, is
not decoded, and has no effect on the cycle that is in progress.
The device is first selected by driving Chip Select (S) Low. Then, the 8-bit instruction code
for the instruction is shifted in. After this, the 24-bit device identification, stored in the
memory, the 17 bytes of UID content will be shifted out on Serial Data output (DQ1). Each
bit is shifted out during the falling edge of Serial Clock (C).
The Read Identification (RDID) instruction is terminated by driving Chip Select (S) High at
any time during data output. When Chip Select (S) is driven High, the device is put in the
Standby Power mode. Once in the Standby Power mode, the device waits to be selected, so
that it can receive, decode and execute instructions.
Read Identification data-out sequence
Extended Device ID table (first byte)
Bit 6
–
–
–
Manufacturer identification (1 byte)
Device identification (2 bytes)
A Unique ID code (UID) (17 bytes, of which 14 factory programmed
Memory type
BAh
Bit 5
Device identification
VCR XIP bit setting:
0 = required,
1 = not required
Memory capacity
19h
Bit 4
Micron Technology, Inc., reserves the right to change products or specifications without notice.
Hold/Reset function:
0 = HOLD,
1 = Reset
EDID+CFD length
10h
Bit 3
Addressing:
0 = by Byte,
©2010 Micron Technology, Inc. All rights reserved.
EDID
2 bytes
Bit 2
UID
Architecture:
00 = Uniform,
CFD
14 bytes
N25Q256 - 3 V
Bit 1
Bit 0