MBM29DL800BA-70 Ver la hoja de datos (PDF) - Spansion Inc.

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MBM29DL800BA-70

8M (1M X 8/512K X 16) BIT

Spansion Inc. 

MBM29DL800TA-70/90/MBM29DL800BA-70/90

Sector Protection

The MBM29DL800TA/BA feature hardware sector protection. This feature will disable both program and erase

operations in any number of sectors (0 through 21). The sector protection feature is enabled using programming

equipment at the user’s site. The devices are shipped with all sectors unprotected. Alternatively, Fujitsu may

program and protect sectors in the factory prior to shiping the device.

To activate this mode, the programming equipment must force VID on address pin A9 and control pin OE, (suggest

VID = 11.5 V), CE = VIL, and A0 = A6 = VIL, A1 = VIH. The sector addresses (A18, A17, A16, A15, A14, A13, and A12)

should be set to the sector to be protected. “Sector Address Tables (MBM29DL800TA/BA)” in sFLEXIBLE

SECTOR-ERASE ARCHITECTURE define the sector address for each of the twenty two (22) 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 “(13) AC Waveforms

for Sector Protection” in sTIMING DIAGRAM and “(5) Sector Protection Algorithm” in sFLOW CHART for sector

protection waveforms and algorithm.

To verify programming of the 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, A13, and A12) while

(A6, A1, A0) = (0, 1, 0) will produce a logical “1” code at device output DQ0 for a protected sector. Otherwise the

devices will read 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.

A-1 requires to apply to VIL on byte mode.

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, A13,

and A12) are the desired sector address will produce a logical “1” at DQ0 for a protected sector. See

“MBM29DL800TA/BA Sector Protection Verify Autoselect Codes Table” and “Extended Autoselect Code Table”

in sDEVICE BUS OPERATION for Autoselect codes.

Temporary Sector Unprotection

This feature allows temporary unprotection of previously protected sectors of the MBM29DL800TA/BA devices

in order to change data. The Sector Unprotection mode is activated by setting the RESET pin to high voltage

(12 V). During this mode, formerly protected sectors can be programmed or erased by selecting the sector

addresses. Once the 12 V is taken away from the RESET pin, all the previously protected sectors will be protected

again. See “(14) Temporary Sector Unprotection Timing Diagram” in sTIMING DIAGRAM and “(6) Temporary

Sector Unprotection Algorithm” in sFLOW CHART.

RESET

Hardware Reset

The MBM29DL800TA/BA devices may be reset by driving the RESET pin to VIL. The RESET pin has a pulse

requirement and has to be kept low (VIL) for at least 500 ns in order to properly reset the internal state machine.

Any operation in the process of being executed will be terminated and the internal state machine will be reset

to the read mode 20 µs after the RESET pin is driven low. Furthermore, once the RESET pin goes high, the

devices require an additional tRH before it will allow read access. When the RESET pin is low, the devices will

be in the standby mode for the duration of the pulse and all the data output pins will be tri-stated. If a hardware

reset occurs during a program or erase operation, the data at that particular location will be corrupted. Please

note that the RY/BY output signal should be ignored during the RESET pulse. See “(9) RESET/RY/BY Timing

Diagram” in sTIMING DIAGRAM for the timing diagram. Refer to Temporary Sector Unprotection for additional

functionality.

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