ACE25C400 Datasheet, PDF (23/31 Pages) ACE Technology Co., LTD. – 4MB Serial Flash Memory

ACE25C400
4MB Serial Flash Memory
Figure 22 Read JEDEC ID instruction
Enter OTP Mode (3Ah)
This Flash has an extra 256 bytes security sector, user must issue ENTER OTP MODE command to
read, program or erase security sector. After entering OTP mode, the security sector is mapping to
sector 63, SRP bit becomes LB and can be read with RDSR command. Program / Erase command
will be disabled when LB is ‘1’
WRSR command will ignore the input data and program LB to 1. User must clear the protect bits
before enter OTP mode.
Security sector can only be program and erase before LB equal ‘1’ and BP[2:0] = ‘000’. In OTP mode,
user can read other sectors, but program/erase other sectors only allowed when LB equal ‘0’.
User can use WRDI (04h) command to exit OTP mode.
Sector Sector size
Adress range
127
256 byte
07F000h-07F0FFh
Table 6 Security sector adress
Note: The secruty sector is mapping to sector 127
VER 1.2 23