MX29GL256EHT2I-90Q Datasheet, PDF (21/76 Pages) Macronix International – DATASHEET

MX29GL256E
COMMAND OPERATIONS
READING THE MEMORY ARRAY
Read mode is the default state after power up or after a reset operation. To perform a read operation, please re-
fer to READ OPERATION in the BUS OPERATIONS section above.
If the device receives an Erase Suspend command while in the Sector Erase state, the erase operation will
pause (after a time delay not exceeding 20us) and the device will enter Erase-Suspended Read mode. While in
the Erase-Suspended Read mode, data can be programmed or read from any sector not being erased. Reading
from addresses within sector (s) being erased will only return the contents of the status register, which is in fact
how the current status of the device can be determined.
If a program command is issued to any inactive (not currently being erased) sector during Erase-Suspended
Read mode, the device will perform the program operation and automatically return to Erase-Suspended Read
mode after the program operation completes successfully.
While in Erase-Suspended Read mode, an Erase Resume command must be issued by the system to reactivate
the erase operation. The erase operation will resume from where is was suspended and will continue until it
completes successfully or another Erase Suspend command is received.
After the memory device completes an embedded operation (automatic Chip Erase, Sector Erase, or Program)
successfully, it will automatically return to Read mode and data can be read from any address in the array. If the
embedded operation fails to complete, as indicated by status register bit Q5 (exceeds time limit flag) going HIGH
during the operations, the system must perform a reset operation to return the device to Read mode.
There are several states that require a reset operation to return to Read mode:
1. A program or erase failure--indicated by status register bit Q5 going HIGH during the operation. Failures dur-
ing either of these states will prevent the device from automatically returning to Read mode.
2. The device is in Auto Select mode or CFI mode. These two states remain active until they are terminated by a
reset operation.
In the two situations above, if a reset operation (either hardware reset or software reset command) is not per-
formed, the device will not return to Read mode and the system will not be able to read array data.
AUTOMATIC PROGRAMMING OF THE MEMORY ARRAY
The device provides the user the ability to program the memory array in Byte mode or Word mode. As long as
the users enters the correct cycle defined in the Table 3 (including 2 unlock cycles and the A0H program com-
mand), any byte or word data provided on the data lines by the system will automatically be programmed into the
array at the specified location.
After the program command sequence has been executed, the internal write state machine (WSM) automatically
executes the algorithms and timings necessary for programming and verification, which includes generating suit-
able program pulses, checking cell threshold voltage margins, and repeating the program pulse if any cells do
not pass verification or have low margins. The internal controller protects cells that do pass verification and mar-
gin tests from being over-programmed by inhibiting further program pulses to these passing cells as weaker cells
continue to be programmed.
With the internal WSM automatically controlling the programming process, the user only needs to enter the pro-
gram command and data once.
P/N:PM1499
REV. 1.8, NOV. 13, 2013
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