M29W400B STMICROELECTRONICS [STMicroelectronics], M29W400B Datasheet - Page 11

• Manufacturer Part Number: M29W400B
• Description: 4 Mbit 512Kb x8 or 256Kb x16, Boot Block Low Voltage Single Supply Flash Memory
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

that is after the fourth W pulse for programming or
after the sixth W pulse for erase. It must be per-
formed at the address being programmed or at an
address within the block being erased. If all the
blocks selected for erasure are protected, DQ7 will
be set to ’0’ for about 100 s, and then return to the
previous addressed memory data value. See Fig-
ure 11 for the Data Polling flowchart and Figure 10
for the Data Polling waveforms. DQ7 will also flag
the Erase Suspend mode by switching from ’0’ to
Table 9. Status Register Bits
Notes: Logic level ’1’ is High, ’0’ is Low. -0-1-0-0-0-1-1-1-0- represent bit value in successive Read operations.
DQ
7
6
5
4
3
2
1
0
Data
Polling
Toggle Bit
Error Bit
Reserved
Erase
Time Bit
Toggle Bit
Reserved
Reserved
Name
’-1-0-1-0-1-0-1-’
’-1-1-1-1-1-1-1-’
’-1-0-1-0-1-0-1-’
Logic Level
DQ
DQ
DQ
DQ
’1’
’0’
’1’
’0’
’1’
’0’
1
Erase Complete or erase
block in Erase Suspend
Erase On-going
Program Complete or data
of non erase block during
Erase Suspend
Program On-going
Erase or Program On-going
Program Complete
Erase Complete or Erase
Suspend on currently
addressed block
Program or Erase Error
Program or Erase On-going
Erase Timeout Period Expired
Erase Timeout Period
On-going
Chip Erase, Erase or Erase
Suspend on the currently
addressed block.
Erase Error due to the
currently addressed block
(when DQ5 = ’1’).
Program on-going, Erase
on-going on another block or
Erase Complete
Erase Suspend read on
non Erase Suspend block
Definition
’1’ at the start of the Erase Suspend. In order to
monitor DQ7 in the Erase Suspend mode an ad-
dress within a block being erased must be pro-
vided. For a Read Operation in Erase Suspend
mode, DQ7 will output ’1’ if the read is attempted
on a blockbeing erasedand the data value on other
blocks. During Program operation in Erase Sus-
pend Mode, DQ7 will have the same behaviour as
in the normal program execution outside of the
suspend mode.
Indicates the P/E.C. status, check during
Program or Erase, and on completion
before checking bits DQ5 for Program or
Erase Success.
Successive reads output complementary
data on DQ6 while Programming or Erase
operations are on-going. DQ6 remains at
constant level when P/E.C. operations are
completed or Erase Suspend is
acknowledged.
This bit is set to ’1’ in the case of
Programming or Erase failure.
P/E.C. Erase operation has started. Only
possible command entry is Erase
Suspend (ES).
An additional block to be erased in parallel
can be entered to the P/E.C.
Indicates the erase status and allows to
identify the erased block
M29W400T, M29W400B
Note
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