MBM29F080A datasheet(14/44 Pages) SPANSION

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MBM29F080A-55/-70/-90

groups will be protected again. Refer to “Temporary Sector Group Unprotection Timing Diagram” in “sTIMING

DIAGRAM” and “Temporary Sector Group Unprotection Algorithm” in “sFLOW CHART”.

Command Definitions

Device operations are selected by writing specific address and data sequences into the command register.

Writing incorrect address and data values or writing them in the improper sequence will reset the device to the

read mode. “MBM29F080A Command Definitions Table” in “sFLEXIBLE SECTOR-ERASE ARCHITECTURE”

defines the valid register command sequences. Note that the Erase Suspend (B0h) and Erase Resume (30h)

commands are valid only while the Sector Erase operation is in progress. Moreover, both Read/Reset commands

are functionally equivalent, resetting the device to the read mode.

Read/Reset Command

The read or reset operation is initiated by writing the read/reset command sequence into the command register.

Microprocessor read cycles retrieve array data from the memory. The device remains enabled for reads until the

command register contents are altered.

The device will automatically power-up in the read/reset state. In this case, a command sequence is not required

to read data. Standard microprocessor read cycles will retrieve array data. This default value ensures that no

spurious alteration of the memory content occurs during the power transition. Refer to the AC Read

Characteristics and Waveforms for the specific timing parameters.

Autoselect Command

Flash memories are intended for use in applications where the local CPU alters memory contents. As such,

manufacture and device codes must be accessible while the device resides in the target system. PROM

programmers typically access the signature codes by raising A9 to a high voltage. However, multiplexing high

voltage onto the address lines is not generally desirable system design practice.

The device contains an autoselect command operation to supplement traditional PROM programming

methodology. The operation is initiated by writing the autoselect command sequence into the command register.

Following the command write, a read cycle from address XX00h retrieves the manufacture code of 04h. A read

cycle from address XX01h returns the device code D5h. (See “MBM29F080A Sector Protection Verify Autoselect

Codes Table” in “sFLEXIBLE SECTOR-ERASE ARCHITECTURE”).

All manufacturer and device codes will exhibit odd parity with the DQ7 defined as the parity bit.

Sector state (protection or unprotection) will be informed by address XX02h.

Scanning the sector group addresses (A17, A18, A19) while (A6, A1, A0) = (0, 1, 0) will produce a logical “1” at

device output DQ0 for a protected sector group.

To terminate the operation, it is necessary to write the read/reset command sequence into the register and also

to write the Autoselect command during the operation, execute it after writing Read/Reset command sequence.

Byte Programming

The device is programmed on a byte-by-byte basis. Programming is a four bus cycle operation. There are two

“unlock” write cycles. These are followed by the program set-up command and data write cycles. Addresses are

latched on the falling edge of CE or WE, whichever happens later and the data is latched on the rising edge of

CE or WE, whichever happens first. The rising edge of CE or WE (whichever happens first) begins programming.

Upon executing the Embedded Program Algorithm command sequence, the system is

not required to provide

further controls or timings. The device will automatically provide adequate internally generated program pulses

and verify the programmed cell margin.

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