Datasheet

16 Mbit Multi-Purpose Flash Plus

SST39VF1681 / SST39VF1682

Data Sheet

Microchip Technology Company

Product Identification

The Product Identification mode identifies the devices as the SST39VF1681 and SST39VF1682, and manu-

facturer as SST. Users may use the software Product Identification operation to identify the part (i.e., using

the device ID) when using multiple manufacturers in the same socket. For details, see Table 6 for software

operation, Figure 12 for the software ID Entry and Read timing diagram, and Figure 22 for the software ID

Entry command sequence flowchart.

Product Identification Mode Exit/CFI Mode Exit

In order to return to the standard Read mode, the Software Product Identification mode must be exited.

Exit is accomplished by issuing the software ID Exit command sequence, which returns the device to

the Read mode. This command may also be used to reset the device to the Read mode after any inad-

vertent transient condition that apparently causes the device to behave abnormally, e.g., not read cor-

rectly. Please note that the software ID Exit/CFI Exit command is ignored during an internal Program or

Erase operation. See Table 6 for software command codes, Figure 14 for timing waveform, and Figures

22 and 23 for flowcharts.

Security ID

The SST39VF168x devices offer a 256-bit Security ID space which is divided into two 128-bit seg-

ments. The first segment is programmed and locked at SST with a random 128-bit number. The user

segment is left un-programmed for the customer to program as desired.

To program the user segment of the Security ID, the user must use the Security ID Byte-Program com-

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

is complete, the Sec ID should be locked using the User Sec ID Program Lock-Out. This disables any

future corruption of this space. Note that regardless of whether or not the Sec ID is locked, neither Sec

ID segment can be erased.

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

ID command (88H) at address AAAH in the last byte sequence. Execute the Exit-Sec-ID command to

exit this mode. Refer to Table 6 for more details.

Table 4: Product Identification

Address Data

Manufacturer’s ID 0000H BFH

Device ID

SST39VF1681 0001H C8H

SST39VF1682 0001H C9H

T4.1 25040