EN25Q40 Datasheet, PDF (36/48 Pages) Eon Silicon Solution Inc. – 4 Megabit Serial Flash Memory with 4Kbyte Uniform Sector

EN25Q40
Figure 24.1. Read Identification (RDID) under EQIO Mode
Enter OTP Mode (3Ah)
This Flash has an extra 256 bytes OTP sector, user must issue ENTER OTP MODE command to read,
program or erase OTP sector. After entering OTP mode, the OTP sector is mapping to sector 127, SRP
bit becomes OTP_LOCK bit and can be read with RDSR command. Program / Erase command will be
disabled when OTP_LOCK bit is ‘1’
WRSR command will ignore the input data and program OTP_LOCK bit to 1.
User must clear the protect bits before enter OTP mode.
OTP sector can only be program and erase before OTP_LOCK bit is set to ‘1’ and BP [2:0] = ‘000’. In
OTP mode, user can read other sectors, but program/erase other sectors only allowed when
OTP_LOCK bit equal to ‘0’.
User can use WRDI (04h) command to exit OTP mode.
The instruction sequence is shown in Figure 25.1 while using the Enable Quad I/O (EQIO) (38h) command.
Erase OTP Command (20h)
User can use Sector Erase (20h) command only to erase OTP data.
Table 7. OTP Sector Address
Sector
Sector Size
Address Range
127
256 byte
07F000h – 07F0FFh
Note: The OTP sector is mapping to sector 127
This Data Sheet may be revised by subsequent versions
36
or modifications due to changes in technical specifications.
©2004 Eon Silicon Solution, Inc.,
Rev. C, Issue Date: 2009/10/13
www.eonssi.com