Datasheet

64 Mbit (x16) Advanced Multi-Purpose Flash Plus

SST38VF6401 / SST38VF6402 / SST38VF6403 / SST38VF6404

Data Sheet

Microchip Technology Company

Security ID

The SST38VF6401/6402/6403/6404 devices offer a Security ID feature. The Secure ID space is divided

into two segments — one factory programmed 128 bit segment and one user programmable 256 word

segment. See Table 7 for address information. The first segment is programmed and locked at SST

and contains a 128 bit Unique ID which uniquely identifies the device. The user segment is left un-pro-

grammed for the customer to program as desired.

The user segment of the Security ID can be programmed in several ways. For smaller datasets, use

the Security ID Word-Program command for word-programming. To program larger sets of data more

quickly, use the SEC ID Entry command to enter the Secure ID space. Once in the Secure ID space,

use the Write-Buffer Programming or Bypass Mode feature. Note that the Word-Programming com-

mand can also be used while in this mode.

To detect end-of-write for the SEC ID, read the toggle bits. Do not use Data# Polling to detect end of

Write. Once the programming is complete, lock the Sec ID by issuing the User Sec ID Program Lock-

Out command or by programming bit ‘0’ in the PSR with the PSR Program command. Locking the Sec

ID disables any corruption of this space. Note that regardless of whether or not the Sec ID is locked,

the Sec ID segments can not be erased.

The Secure ID space can be queried by executing a three-byte command sequence with Enter Sec ID

command (88H) at address 555H in the last byte sequence. To exit this mode, the Exit Sec ID com-

mand should be executed. Refer to Table 11 for software commands and Figures 27 and 28 for flow

charts.

Bypass Mode

Bypass mode shortens the time needed to issue program and erase commands by reducing these

commands to two write cycles each. After using the Bypass Entry command to enter the Bypass

mode, only the Bypass Word-Program, Bypass Sector Erase, Bypass Block Erase, Bypass Chip

Erase, Erase-Suspend, and Erase-Resume commands are available. The Bypass Exit command exits

Bypass mode. See Table 11 for further details.

Entering Bypass Mode while already in Erase-Suspend limits the available commands. See “Erase-

Suspend/Erase-Resume Commands” on page 11. for more information.

Table 7: Address Range for Sec ID

Size Address

SST Unique ID 128 bits 000H – 007H

User 256 W 100H – 1FFH

T7.1 25015