MBM29PL65LM90TN datasheet(16/56 Pages) SPANSION

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MBM29PL65LM-90/10

Page Mode Read

The device is capable of fast Page mode read and are compatible with Page mode Mask ROM read operation.

This mode provides faster read access speed for random locations within a page. Page size is 4 words, within

the appropriate Page being selected by the higher address bits A21 to A2 and the address bits A1 to A0 in Word

mode (A1 to A-1 in Byte mode). The initial page access is equal to the random access (tACC) and subsequent

Page read access (as long as the locations specified by the microprocessor fall within that Page) is equivalent

to the page access time (tPACC).

Output Disable

With the OE input is at logic high level (VIH), output from the device is disabled. This causes the output pins to

be in a high impedance state.

Write

Device erase and programming are accomplished via the command register. The contents of the register serve

as input to the internal state machine. The state machine output dictates the device function.

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 starts later, while data is latched on the rising edge of WE or CE, whichever

starts first. Standard microprocessor write timings are used.

Refer to AC Write Characteristics and the Erase/Programming Waveforms for specific timing parameters.

Sector Group Protection

The device features hardware sector group protection. This feature will disable both program and erase opera-

tions in any combination of 32 sector groups of memory. See “Sector Group Address Table (MBM29PL65LM)”

in “s DEVICE BUS OPERATION”. The user’s side can use the sector group protection using programming

equipment. The device is shipped with all sector groups that are unprotected.

To activate it, the programming equipment must force VID on address pin A9 and control pin OE, CE = VIL and

A6 = A3 = A2 = A0 = VIL, A1 = VIH. The sector group addresses (A21, A20, A19, A18, and A17) should be set to the

sector to be protected. “Sector Address Table (MBM29PL65LM)” in “s DEVICE BUS OPERATION” defines the

sector address for each of the seventy-one (71) individual sectors, and “Sector Group Address Table

(MBM29PL65LM)” in “s DEVICE BUS OPERATION” defines the sector group address for each of the twenty-

four (24) individual group 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 group addresses must be held constant during

the WE pulse. See “Sector Group Protection Timing Diagram” in “s TIMING DIAGRAM” and “Sector Group

Protection Algorithm” in “s FLOW CHART” for sector group protection timing diagram 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 group addresses (A21, A20, A19, A18 and A17) while (A6,

A3, A2, A1, A0) = (0, 0, 0, 1, 0) will produce a logical “1” code at device output DQ0 for a protected sector. Otherwise

the device will produce “0” for unprotected sectors. In this mode, the lower order addresses, except for A0, A1,

A2, A3 and A6 can be either High or Low.

Where the high order addresses (A21, A20, A19, A18 and A17) are the desired sector group address will produce a

logical “1” at DQ0 for a protected sector group. See “Sector Group Protection Verify Autoselect Codes” in

“s DEVICE BUS OPERATION” for Autoselect codes.

Temporary Sector Group Unprotection

This feature allows temporary unprotection of previously protected sector groups of the devices in order to change

data. The Sector Group Unprotection mode is activated by setting the RESET pin to high voltage (VID). During

this mode, formerly protected sector groups can be programmed or erased by selecting the sector group ad-

dresses. Once the VID is taken away from the RESET pin, all the previously protected sector groups will be

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