MX29F400T/B
CHIP UNPROTECTION ALGORITHM FOR SYSTEM WITHOUT 12V
P/N:PM0439
START
Protect All Sectors
PLSCNT=1
Write "unlock for sector protect/unprotect"
Command (Table 1)
Set OE=A9=VIH
CE=VIL,A6=1
Activate WE Pulse to start
Data don't care
No
Toggle bit checking
Q6 not Toggled
Yes
Set OE=CE=VIL
A9=VIH,A1=1
Set Up First Sector Addr
Increment
PLSCNT
Increment
Sector Addr
Read Data from Device
No
Data=00H?
Yes
No
All sectors have
been verified?
Yes
Write Reset Command
Chip Unprotect
Complete
No
PLSCNT=1000?
Yes
Device Failed
* It is recommended before unprotect whole chip, all sectors should be protected in advance.
37
REV. 1.6, NOV. 12, 2001