W25Q64DW_12 Datasheet, PDF (61/82 Pages) Winbond – 1.8V 64M-BIT SERIAL FLASH MEMORY WITH DUAL/QUAD SPI & QPI

W25Q64DW
10.2.36 Program Security Registers (42h)
The Program Security Register instruction is similar to the Page Program instruction. It allows from one
byte to 256 bytes of security register data to be programmed at previously erased (FFh) memory locations.
A Write Enable instruction must be executed before the device will accept the Program Security Register
Instruction (Status Register bit WEL= 1). The instruction is initiated by driving the /CS pin low then shifting
the instruction code “42h” followed by a 24-bit address (A23-A0) and at least one data byte, into the DI pin.
The /CS pin must be held low for the entire length of the instruction while data is being sent to the device.
ADDRESS
Security Register #0*
Security Register #1
Security Register #2
Security Register #3
A23-16
00h
00h
00h
00h
A15-12
0000
0001
0010
0011
A11-8
0000
0000
0000
0000
A7-0
Byte Address
Byte Address
Byte Address
Byte Address
* Please note that Security Register 0 is Reserved by Winbond for future use. It is
recommended to use Security registers 1- 3 before using register 0.
The Program Security Register instruction sequence is shown in Figure 35. The Security Register Lock
Bits (LB3-0) in the Status Register-2 can be used to OTP protect the security registers. Once a lock bit is
set to 1, the corresponding security register will be permanently locked, Program Security Register
instruction to that register will be ignored (See 11.1.9, 11.2.21 for detail descriptions).
/CS
CLK
Mode 3
Mode 0
0 1 2 3 4 5 6 7 8 9 10
28 29 30 31 32 33 34 35 36 37 38 39
DI
(IO₀)
/CS
* ^{= MSB}
Instruction (42h)
24-Bit Address
Data Byte 1
23 22 21
*
321076543210
*
CLK
DI
(IO₀)
39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55
Data Byte 2
Data Byte 3
07654321076543210
*
*
Data Byte 256
76543210
*
Mode 3
Mode 0
Figure 35. Program Security Registers Instruction (SPI Mode only)
- 61 -
Publication Release Date: September 18, 2012
Revision D