This Data Sheet may be revised by subsequent versions

©2004 Eon Silicon Solution, Inc., www.essi.com.tw

or modifications due to changes in technical specifications.

20

EN25F80

Rev. E, Issue Date: 2007/11/23

Figure 19. Read Identification (RDID)

Enter OTP Mode (3Ah)

This Flash has a extra 256 bytes OTP sector, user must issue ENTER OTP MODE command to

enter OTP mode before reading / programming or erasing OTP sector. After entering OTP mode,

the OTP sector is mapping to sector 255,

SRP bit becomes OTP_LOCK bit and can be read with

RDSR command. Program / Erase command will be disabled when OTP_LOCK is ‘1’

WRSR command will ignore the input data and program LOCK_BIT to 1.

User must clear the protect bits before enter OTP mode.

OTP sector can only be program and erase when LOCK_BIT equal ‘0’ and BP [2:0] = ‘000’. In OTP

mode, user can read other sectors, but program/erase other sectors only allowed when OTP_LOCK

equal ‘0’.

User can use WRDI (04H) command to exit OTP mode.

Figure 20. Enter OTP Mode