L800BT90VC datasheet(16/49 Pages) AMD

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Am29LV800B

Autoselect Mode

The autoselect mode provides manufacturer and

device identification, and sector protection verifica-

tion, through identifier codes output on DQ7–DQ0.

This mode is primarily intended for programming

equipment to automatically match a device to be pro-

grammed with its corresponding programming algo-

rithm. However, the autoselect codes can also be

accessed in-system through the command register.

When using programming equipment, the autoselect

mode requires VID (11.5 V to 12.5 V) on address pin

A9. Address pins A6, A1, and A0 must be as shown in

Table 4. In addition, when verifying sector protection,

the sector address must appear on the appropriate

highest order address bits (see Tables 2 and 3). Table

4 shows the remaining address bits that are don’t

care. When all necessary bits have been set as

required, the programming equipment may then read

the corresponding identifier code on DQ7–DQ0.

To access the autoselect codes in-system, the host

system can issue the autoselect command via the

command register, as shown in Table 1. This method

does not require VID. See “Command Definitions” for

details on using the autoselect mode.

Table 4. Am29LV800B Autoselect Codes (High Voltage Method)

L = Logic Low = VIL, H = Logic High = VIH, SA = Sector

Address, X = Don’t care.

Sector Protection/Unprotection

The hardware sector protection feature disables both

program and erase operations in any sector. The

hardware sector unprotection feature re-enables both

program and erase operations in previously protected

sectors.

The device is shipped with all sectors unprotected.

AMD offers the option of programming and protecting

sectors at its factory prior to shipping the device

through AMD’s ExpressFlash™ Service. Contact an

AMD representative for details.

It is possible to determine whether a sector is pro-

tected or unprotected. See “Autoselect Mode” for

details.

Sector Protection/unprotection can be implemented

via two methods.

The primary method requires VID on the RESET# pin

only, and can be implemented either in-system or via

programming equipment. Figure 2 shows the algo-

rithms and Figure 23 shows the timing diagram. This

method uses standard microprocessor bus cycle

timing. For sector unprotect, all unprotected sectors

must first be protected prior to the first sector unpro-

tect write cycle.

The alternate method intended only for programming

equipment requires VID on address pin A9 and OE#.

This method is compatible with programmer routines

written for earlier 3.0 volt-only AMD flash devices.

Publication number 20536 contains further details;

contact an AMD representative to request a copy.

Temporary Sector Unprotect

This feature allows temporary unprotection of previ-

ously protected sectors to change data in-system.

The Sector Unprotect mode is activated by setting the

RESET# pin to VID. During this mode, formerly pro-

tected sectors can be programmed or erased by

selecting the sector addresses. Once VID is removed

from the RESET# pin, all the previously protected

sectors are protected again. Figure 1 shows the algo-

rithm, and Figure 22 shows the timing diagrams, for

this feature.

Description

Mode

CE#

OE# WE#

A18

A12

A11

A10

DQ8

DQ15

DQ7

DQ0

Manufacturer ID: AMD

VID

01h

Device ID:

Am29LV800B

(Top Boot Block)

Word

VID

22h

DAh

Byte

DAh

Device ID:

Am29LV800B

(Bottom Boot

Block)

Word

VID

22h

5Bh

Byte

5Bh

Sector Protection

Verification

VID

01h

(protected)

00h

(unprotected

)

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