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參數(shù)資料
| 型號： | AM29F400AT |
| 廠商： | Advanced Micro Devices, Inc. |
| 英文描述： | 4 Megabit (524,288 x 8-Bit/262,144 x 16-Bit) CMOS 5.0 Volt-only, Sector Erase Flash Memory |
| 中文描述： | 4兆位（524,288 x 8-Bit/262，144 x 16位），5.0伏的CMOS只，扇區(qū)擦除閃存 |
| 文件頁數(shù)： | 15/35頁 |
| 文件大?。?/td> | 136K |
| 代理商： | AM29F400AT |
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Am29F400AT/Am29F400AB
15
P R E L I M I N A R Y
5
DQ7
Data
Polling
The Am29F400A device features Data Polling as a
method to indicate to the host that the embedded algo-
rithms are in progress or completed. During
the Embedded Program Algorithm an attempt to read
the device will produce the complement of the data last
written to DQ7. Upon completion of the Embedded Pro-
gram Algorithm, an attempt to read the device will pro-
duce the true data last written to DQ7. During the
Embedded Erase Algorithm, an attempt to read
the device will produce a “0” at the DQ7 output.
Upon completion of the Embedded Erase Algorithm an
attempt to read the device will produce a “1” at the DQ7
output. The flowchart for Data Polling (DQ7) is shown
in Figure 2.
For chip erase, the Data Polling is valid after the rising
edge of the sixth WE pulse in the six write pulse se-
quence. For sector erase, the Data Polling is valid after
the last rising edge of the sector erase WE pulse. Data
Polling must be performed at sector addresses within
any of the sectors being erased and
not
a protected
sector. Otherwise, the status may not be valid.
Just prior to the completion of Embedded Algorithm
operations DQ7 may change asynchronously while
the output enable (OE) is asserted low. This means
that the device is driving status information on DQ7 at
one instant of time and then that byte’s valid data at
the next instant of time. Depending on when the sys-
tem samples the DQ7 output, it may read the status or
valid data. Even if the device has completed the Em-
bedded Algorithm operations and DQ7 has a valid
data, the data outputs on DQ0–DQ6 may be still in-
valid. The valid data on DQ0–DQ7 will be read on the
successive read attempts.
The Data Polling feature is only active during the Em-
bedded Programming Algorithm, Embedded Erase Al-
gorithm, or sector erase time-out (see Table 7).
See Figure 10 for the Data Polling timing specifications
and diagrams.
DQ6
Toggle Bit
The Am29F400A also features the “Toggle Bit” as a
method to indicate to the host system that the embed-
ded algorithms are in progress or completed.
During an Embedded Program or Erase Algorithm cy-
cle, successive attempts to read (OE toggling) data
from the device at any address will result in DQ6 tog-
gling between one and zero. Once the Embedded Pro-
gram or Erase Algorithm cycle is completed, DQ6 will
stop toggling and valid data will be read on the next
successive attempt. During programming, the Toggle
Bit is valid after the rising edge of the fourth WE pulse
in the four write pulse sequence. For chip erase, the
Toggle Bit is valid after the rising edge of the sixth WE
pulse in the six write pulse sequence. For Sector erase,
the Toggle Bit is valid after the last rising edge of the
sector erase WE pulse. The Toggle Bit is active during
the sector time-out.
Either CE or OE toggling will cause DQ6 to toggle. In
addition, an Erase Suspend/Resume command will
cause DQ6 to toggle. See Figure 11 for the Toggle Bit
timing specifications and diagrams.
DQ5
Exceeded Timing Limits
DQ5 will indicate if the program or erase time has ex-
ceeded the specified limits (internal pulse count).
Under these conditions DQ5 will produce a “1”. This is
a failure condition which indicates that the program or
erase cycle was not successfully completed. Data Poll-
ing is the only operating function of the device under
this condition. The CE circuit will partially power down
the device under these conditions (to approximately 2
mA). The OE and WE pins will control the output dis-
able functions as described in Table 1.
The DQ5 failure condition will also appear if a user tries
to program a 1 to a location that is previously pro-
grammed to 0. In this case the device locks out and
never completes the Embedded Program Algorithm.
Hence, the system never reads a valid data on DQ7 bit
and DQ6 never stops toggling. Once the device has ex-
ceeded timing limits, the DQ5 bit will indicate a “1.”
Please note that this is not a device failure condition
since the device was incorrectly used. If this occurs,
reset the device.
DQ3
Sector Erase Timer
After the completion of the initial sector erase com-
mand sequence the sector erase time-out will begin.
DQ3 will remain low until the time-out is complete. Data
Polling and Toggle Bit are valid after the initial sector
erase command sequence.
If Data Polling or the Toggle Bit indicates the device has
been written with a valid erase command, DQ3 may be
used to determine if the sector erase timer window is
still open. If DQ3 is high (“1”) the internally controlled
erase cycle has begun; attempts to write subsequent
commands (other than Erase Suspend) to the device
will be ignored until the erase operation is completed as
indicated by Data Polling or Toggle Bit. If DQ3 is low
(“0”), the device will accept additional sector erase
commands. To insure the command has been ac-
cepted, the system software should check the status of
DQ3 prior to and following each subsequent sector
erase command. If DQ3 were high on the second sta-
tus check, the command may not have been accepted.
Refer to Table 8: Write Operation Status.
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| Am29F400AT-65FCB | 4 Megabit (524,288 x 8-Bit/262,144 x 16-Bit) CMOS 5.0 Volt-only, Sector Erase Flash Memory |
| Am29F400AT-65FIB | 4 Megabit (524,288 x 8-Bit/262,144 x 16-Bit) CMOS 5.0 Volt-only, Sector Erase Flash Memory |
| AM29F400BB-90DGE1 | 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only, Boot Sector Flash Memory-Die Revision 1 |
| AM29F400B-1 | 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only, Boot Sector Flash Memory-Die Revision 1 |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AM29F400AT-120SC | 制造商:Advanced Micro Devices 功能描述:Flash Mem Parallel 5V 4M-Bit 512K x 8/256K x 16 120ns 44-Pin SO |
| AM29F400AT-90SC | 制造商:Advanced Micro Devices 功能描述:NOR Flash, 256K x 16, 44 Pin, Plastic, SOP |
| AM29F400BB | 制造商: 功能描述: 制造商:undefined 功能描述: |
| AM29F400BB120EC | 制造商:AMD 功能描述:New |
| AM29F400BB-120SC | 制造商:Advanced Micro Devices 功能描述: |
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