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.

21

EN25F80

Rev. D, Issue Date: 2007/05/16

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 reading by 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 sector 255 not protected. 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