MBM29PL64LM datasheet(25/69 Pages) SPANSION

25 / 69 page

MBM29PL64LM90/10

Programming is allowed in any address sequence and across sector boundaries. Beware that a data “0” cannot

be programmed back to a “1”. Attempting to do so may result in either failure condition or an apparent success

according to the data polling algorithm. But a read from Reset mode will show that the data is still “0”. Only erase

operations can convert “0”s to “1”s.

Note that attempting to program a “1” over a “0” will result in programming failure. This precaution is the same

with Fujitsu standard NOR devices. “Embedded ProgramTM Algorithm” in sFLOW CHART illustrates the Em-

bedded ProgramTM Algorithm using typical command strings and bus operations.

Program Suspend/Resume

The Program Suspend command allows the system to interrupt a program operation so that data can be read

from any address. Writing the Program Suspend command (B0h) during Embedded Program operation imme-

diately suspends the programming. Refer to "Erase Suspend/Resume" for the detail.

When the Program Suspend command is written during a programming process, the device halts the program

operation within 1us and updates the status bits.After the program operation has been suspended, the system

can read data from any address. The data at program-suspended address is not valid. Normal read timing and

command definitions apply.

After the Program Resume command (30h) is written, the device reverts to programming. The system can

determine the status of the program operation using the DQ7 or DQ6 status bits, just as in the standard program

operation. See "Write Operation Status" for more information. When issuing program suspend command in

µs after issuing program command, determine the status of program operation by reading status bit at more

µs after issuing program resume command.

The system also writes the Autoselect command sequence in the Program Suspend mode. The device allows

reading Autoselect codes at the addresses within programming sectors, since the codes are not stored in the

memory. When the device exits the Autoselect mode, the device reverts to the Program Suspend mode, and is

ready for another valid operation. See "Autoselect Command Sequence" for more information.

The system must write the Program Resume command to exit from the Program Suspend mode and continue

the programming operation. Further writes of the Resume command are ignored. Another Program Suspend

command can be written after the device resumes programming. Do not read CFI code after HiddenROM Entry

and Exit in program suspend mode.

Write Buffer Programming Operations

Write Buffer Programming allows the system write to series of 16 words in one programming operation. This

results in faster effective word programming time than the standard programming algorithms. The Write Buffer

Programming command sequence is initiated by first writing two unlock cycles. This is followed by a third write

cycle selecting the Sector Address in which programming will occur. In forth cycle contains both Sector Address

and unique code for data bus width will be loaded into the page buffer at the Sector Address in which programming

will occur.

The system then writes the starting address/data combination. This “starting address” must be the same Sector

Address used in third and fourth cycles and its lower addresses of A3 to A0 should be 0h. All subsequent address

must be incremented by 1. 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) starts programming. Upon executing the Write Buffer Programming Operations com-

mand 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.

DQ7(Data Polling), DQ6(Toggle Bit), DQ5(Exceeded Timing Limits), DQ1(Write-to-Buffer Abort) should be moni-

tored to determine the device status during Write Buffer Programming. In addition to these functions, it is also

possible to indicate to the host system that Write Buffer Programming Operations are either in progress or have

been completed by RY/BY. See “Hardware Sequence Flags”.

The Data polling techniques described in “Data Polling Algorithm” in sFLOW CHART should be used while

monitoring the last address location loaded into the write buffer. In addition, it is not neccessary to specify an

address in Toggle Bit techniques described in “Toggle Bit Algorithm” in sFLOW CHART. The automatic pro-

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