MBM29F004TC-70PD datasheet(13/53 Pages) SPANSION

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MBM29F004TC/004BC-70/90

Sector Group Protection

The MBM29F004TC/BC features hardware sector group protection. These features will disable both program

and erase operations in any combination of sectors (0 through 10) . The sector group protection feature is enabled

using programming equipment at the user’s site. The device is shipped with all sector group unprotected.

To activate command mode sector group protection, the programming groups equipment must force VID on

address pin A9 and control pin OE, (suggest VID

= 12 V) , CE = VIL, A6 = VIL. The sector addresses (A18, A17,

A16, A15, A14, and A13) should be set to the sector to be protected. Tables 5 and 6 define the sector address for

each of the eleven (11) individual sectors. Programming of the protection circuitry begins on the falling edge of

the WE pulse and is terminated with the rising edge of the same. Sector addresses must be held constant during

the WE pulse. See figures 12 and 20 for sector protection waveforms and algorithm.

To verify programming of the command mode sector protection circuitry, the programming equipment must force

VID on address A9 with CE and OE at VIL and WE at VIH. Scanning the sector addresses (A18, A17, A16, A15, A14,

and A13) while (A6, A5, A1, A0)

= (0, 1, 1, 0) will produce a logical “1” code at device output DQ0 for a protected

sector. Otherwise the device will produce 00h for unprotected sector. In this mode, the lower order addresses,

except for A0, A1, A5, and A6 are DON’T CARES. Address locations with A1

= VIL are reserved for Autoselect

manufacturer and device codes.

The alternate hardware sector protect mode intended only for the programming equipment required force VID

on address pin A9 and control pin OE, (suggest VID

= 12 V) , CE = VIL. The sector addresses (A18, A17, A16, A15,

A14, and A13) should be set to the sector to be protected. Tables 4 and 5 define the sector address for each of

the eleven (11) individual sectors. Programming of the protection circuitry begins on the falling edge of the WE

pulse and is terminated with the rising edge of the same. Sector addresses must be held constant during the

WE pulse. See figures 15 and 23 for sector protection waveforms and algorithm.

To verify programming of the hardware sector protection circuitry, the programming equipment must force VID

on address pin A9 with CE and OE at VIL and WE at VIH. Scanning the sector addresses (A18, A17, A16, A15, A14,

and A13) while (A6, A1, A0)

= (0, 1, 0) will produce a logical “1” code at device output DQ0 for a protected sector.

Otherwise the device will produce 00h for unprotected sector. In this mode, the lower order addresses, except

for A0, A1, and A6 are DON’T CARES. Address locations with A1

= VIL are reserved for Autoselect manufacturer

and device codes.

It is also possible to determine if a sector is protected in the system by writing an Autoselect command. Performing

a read operation at the address location XX02h, where the higher order addresses (A18, A17, A16, A15, A14, and

A13) are the desired sector group address will produce a logical “1” at DQ0 for a protected sector group. See

Tables 3.1 and 3.2 for Autoselect codes.

Temporary Sector Unprotection

This feature allows temporary unprotect of previously protected sector of the MBM29F004TC/BC device in order

to change data. The Temporary Sector Unprotection mode is activated by setting the OE pin to high voltage (12

V) . While OE is at VID, the sector unlock sequence is written to the device. After the sector unlock sequence is

written, the OE pin is taken back to VIH. The device is now in the Temporary Sector Unprotection mode.

While in this mode, formerly protected sectors can be programmed or erased by selecting the appropriate sector

addresses during programming or erase operations. Either sector erase or chip erase operations can be per-

formed in this mode. Exiting the Temporary Sector unprotection mode is accomplished by either removing VCC

from the device or by taking OE back to VID and writing the sector relock sequence. After writing the sector relock

sequence, the OE pin is taken back to VIH and all previously protected sectors will be protected again.

The Temporary Sector Unprotection Status can be used to check whether this mode is in operation or not. The

Temporary Sector Unprotection Status can be executed by setting AO

= AI = VIH (A6 = VIL) during Autoselect mode.

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