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参数资料
| 型号： | Am29F400BT-90SCB |
| 厂商： | Advanced Micro Devices, Inc. |
| 英文描述： | 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory |
| 中文描述： | 4兆位（512亩x 8-Bit/256亩x 16位），5.0伏的CMOS只引导扇区闪存 |
| 文件页数： | 18/37页 |
| 文件大小： | 238K |
| 代理商： | AM29F400BT-90SCB |
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18
Am29F400B
P R E L IM IN A R Y
The remaining scenario is that the system initially de-
termines that the toggle bit is toggling and DQ5 has not
gone high. The system may continue to monitor the
toggle bit and DQ5 through successive read cycles, de-
termining the status as described in the previous para-
graph. Alternatively, it may choose to perform other
system tasks. In this case, the system must start at the
beginning of the algorithm when it returns to determine
the status of the operation (top of Figure 5).
DQ5: Exceeded Timing Limits
DQ5 indicates whether the program or erase time has
exceeded a specified internal pulse count limit. Under
these conditions DQ5 produces a “1.” This is a failure
condition that indicates the program or erase cycle was
not successfully completed.
The DQ5 failure condition may appear if the system
tries to program a “1” to a location that is previously pro-
grammed to “0.”
Only an erase operation can change
a “0” back to a “1.”
Under this condition, the device
halts the operation, and when the operation has ex-
ceeded the timing limits, DQ5 produces a “1.”
Under both these conditions, the system must issue the
reset command to return the device to reading array
data.
DQ3: Sector Erase Timer
After writing a sector erase command sequence, the
system may read DQ3 to determine whether or not an
erase operation has begun. (The sector erase timer
does not apply to the chip erase command.) If addi-
tional sectors are selected for erasure, the entire time-
out also applies after each additional sector erase
command. When the time-out is complete, DQ3
switches from “0” to “1.” If the time between additional
sector erase commands from the system can be as-
sumed to be less than 50 μs, the system need not
monitor DQ3. See also the “Sector Erase Command
Sequence” section.
After the sector erase command sequence is written,
the system should read the status on DQ7 (Data# Poll-
ing) or DQ6 (Toggle Bit I) to ensure the device has ac-
cepted the command sequence, and then read DQ3. If
DQ3 is “1”, the internally controlled erase cycle has be-
gun; all further commands (other than Erase Suspend)
are ignored until the erase operation is complete. If
DQ3 is “0”, the device will accept additional sector
erase commands. To ensure the command has been
accepted, the system software should check the status
of DQ3 prior to and following each subsequent sector
erase command. If DQ3 is high on the second status
check, the last command might not have been ac-
cepted. Table 6 shows the outputs for DQ3.
START
No
Yes
Yes
DQ5 = 1
No
Yes
Toggle Bit
= Toggle
No
Program/Erase
Operation Not
Complete, Write
Reset Command
Program/Erase
Operation Complete
Read DQ7–DQ0
Toggle Bit
= Toggle
Read DQ7–DQ0
Twice
Read DQ7–DQ0
Notes:
1. Read toggle bit twice to determine whether or not it is
toggling. See text.
2. Recheck toggle bit because it may stop toggling as DQ5
changes to “1”. See text.
21505C-9
Figure 5.
Toggle Bit Algorithm
(Notes
1, 2)
(Note 1)
相关PDF资料 |
PDF描述 |
|---|---|
| AM29F400BT-90SE | 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory |
| AM29F400BT-90SEB | 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory |
| AM29F400BT-90SI | 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory |
| Am29F400BT-90SIB | 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory |
| AM29F400BT-90SC0 | 4 Megabit (512 K x 8-Bit/256 K x 16-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AM29F400BT-90SE\T | 制造商:Spansion 功能描述:4 MEGABIT (512 K X 8-BIT/256 K X 16-BIT) CMOS 5.0 VOLT-ONLY BOOT SECTOR FLASH MEMORY |
| AM29F400BT-90SF\\T | 制造商:Spansion 功能描述:NOR Flash Parallel 5V 4Mbit 512K/256K x 8bit/16bit 90ns 44-Pin SO T/R |
| AM29F400BT-90SF\T | 制造商:Spansion 功能描述:NOR Flash Parallel 5V 4Mbit 512K/256K x 8bit/16bit 90ns 44-Pin SO T/R |
| AM29F400BT-90SI | 制造商:Spansion 功能描述: |
| AM29F800BB-120DPC1 | 制造商:Spansion 功能描述:5V 8M FLASH KNOWN GOOD DIE W/BOTTOM BOOT (COMMERCIAL TEMP) - Gel-pak, waffle pack, wafer, diced wafer on film |
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