MBM29LV160TE/BE-70/90/12
• Write
Device erasure and programming are accomplished via the command register. The contents of the register serve
as inputs to the internal state machine. The state machine outputs dictate the function of the device.
The command register itself does not occupy any addressable memory location. The register is a latch used to
store the commands, along with the address and data information needed to execute the command. The com-
mand register is written by bringing WE to VIL, while CE is at VIL and OE is at VIH. Addresses are latched on the
falling edge of WE or CE, whichever happens later; while data is latched on the rising edge of WE or CE,
whichever happens first. Standard microprocessor write timings are used.
Refer to AC Write Characteristics and the Erase/Programming Waveforms for specific timing parameters.
• Sector Protection
The MBM29LV160TE/BE features hardware sector protection. This feature will disable both program and erase
operations in any number of sectors (0 through 34). The sector protection feature is enabled using programming
equipment at the user’s site. The device is shipped with all sectors unprotected.
To activate this mode, the programming equipment must force VID on address pin A9 and control pin OE, CE =
VIL, A0 = A6 = VIL, A1 = VIH. The sector addresses pins (A19, A18, A17, A16, A15, A14, A13, and A12) should be set to
the sector to be protected. Tables 5 and 6 define the sector address for each of the thirty five (35) 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 17
and 24 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 (A19, A18, A17, A16, A15, A14, A13, and A12)
while (A6, A1, A0) = (0, 1, 0) will produce a logical “1” at device output DQ0 for a protected sector. Otherwise the
device will read 00H for an 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 VIL in 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 pins (A19, A18, A17, A16, A15,
A14, A13, and A12) represents the sector address will produce a logical “1” at DQ0 for a protected sector. See
Tables 4.1 and 4.2 for Autoselect codes.
• Temporary Sector Unprotection
This feature allows temporary unprotection of previously protected sectors of the MBM29LV160TE/BE devices
in order to change data. The Sector Unprotection mode is activated by setting the RESET pin to high voltage
(VID). During this mode, formerly protected sectors can be programmed or erased by selecting the sector ad-
dresses. Once the VID is taken away from the RESET pin, all the previously protected sectors will be protected
again. (See Figures 18 and 25.)
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