Datasheet

©2011 Silicon Storage Technology, Inc. DS-25015A 04/11
21
64 Mbit (x16) Advanced Multi-Purpose Flash Plus
SST38VF6401 / SST38VF6402 / SST38VF6403 / SST38VF6404
Data Sheet
A
Microchip Technology Company
The password can be read using the Password Read command to verify the desired password has
been programmed. SST recommends testing the password before permanently choosing Password
Mode.
To test the password, do the following:
1. Enter the Global Lock of NVPBs mode.
2. Set the Global Lock Bit to ‘0’, and verify the value.
3. Exit the Global Lock of NVPBs mode.
4. Enter the Password Commands mode.
5. Submit the 64-bit password with the Submit Password command.
6. Wait 2 µs for the device to verify the password.
7. Exit the Password Commands mode.
8. Re-enter the Global Lock of NVPBs mode
9. Read the Global Lock Bit with the Global Lock Bit Status Read command. The Global
Lock bit should now be ‘1’.
After verifying the password, program the DQ
2
and DQ
1
OTP bits of the PSR to explicitly choose Pass-
word mode. Once the Password mode has been selected, the Password Read and Password Program
commands are permanently disabled. There is no longer any method for reading or modifying the
password. In addition, SST is unable to read or modify the password. If a Password Read command is
issued while in Password mode, the data presented for each word of the password is FFFFh.
If the Password Mode is not explicitly chosen in the PSR, then the password can still be read and mod-
ified. Therefore, SST strongly recommends that users explicitly choose Password Mode in the PSR.