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AM29BDS64HE9VKI 参数 Datasheet PDF下载

AM29BDS64HE9VKI图片预览
型号: AM29BDS64HE9VKI
PDF下载: 下载PDF文件 查看货源
内容描述: 128或64兆比特( 8 M或4米×16位) CMOS 1.8伏只同步读/写,突发模式闪存 [128 or 64 Megabit (8 M or 4 M x 16-Bit) CMOS 1.8 Volt-only Simultaneous Read/Write, Burst Mode Flash Memory]
分类和应用: 闪存
文件页数/大小: 89 页 / 1587 K
品牌: SPANSION [ SPANSION ]
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D A T A S H E E T  
tection Mode Locking Bit is programmed. If not, the command is accomplished by writing the Read/Reset  
system must repeat this program sequence from the  
fourth cycle of “PL/68h”. Exiting the Persistent Protec-  
tion Mode Locking Bit Program command is accom-  
plished by writing the SecSi Sector Exit command or  
Reset command.  
command.  
Password Unlock Command  
The Password Unlock command is used to clear the  
PPB Lock Bit so that the PPBs can be unlocked for  
modification, thereby allowing the PPBs to become ac-  
cessible for modification. The exact password must be  
entered in order for the unlocking function to occur.  
This command cannot be issued any faster than 2 µs  
at a time to prevent a hacker from running through the  
all 64-bit combinations in an attempt to correctly match  
a password. If the command is issued before the 2 µs  
execution window for each portion of the unlock, the  
command will be ignored.  
SecSi Sector Protection Bit Program  
Command  
To protect the SecSi Sector, write the SecSi Sector  
Protect command sequence while in the SecSi Sector  
mode. After issuing “OPBP/48h” at the fourth bus cy-  
cle, the device requires a time out period of approxi-  
mately 150 µs to protect the SecSi Sector. Then, by  
writing “OPBP/48” at the fifth bus cycle, the device out-  
puts verify data at DQ0. If DQ0 = 1, then the SecSi  
Sector is protected. If not, then the system must re-  
peat this program sequence from the fourth cycle of  
“OPBP/48h”.  
The Password Unlock function is accomplished by  
writing Password Unlock command and data to the de-  
vice to perform the clearing of the PPB Lock Bit. The  
password is 64 bits long, so the user must write the  
Password Unlock command 4 times. A1 and A0 are  
used for matching. Writing the Password Unlock com-  
mand is not address order specific. The lower address  
A1–A0= 00, the next Password Unlock command is to  
A1–A0= 01, then to A1–A0= 10, and finally to A1–A0=  
11.  
PPB Lock Bit Set Command  
The PPB Lock Bit Set command is used to set the  
PPB Lock bit if it is cleared either at reset or if the  
Password Unlock command was successfully exe-  
cuted. There is no PPB Lock Bit Clear command.  
Once the PPB Lock Bit is set, it cannot be cleared un-  
less the device is taken through a power-on clear or  
the Password Unlock command is executed. Upon set-  
ting the PPB Lock Bit, the PPBs are latched into the  
DYBs. If the Password Mode Locking Bit is set, the  
PPB Lock Bit status is reflected as set, even after a  
power-on reset cycle. Exiting the PPB Lock Bit Set  
command is accomplished by writing the SecSi Sector  
Exit command, only while in the Persistent Sector Pro-  
tection Mode.  
Once the Password Unlock command is entered for all  
four words, the RDY pin goes LOW indicating that the  
device is busy. Approximately 1 µs is required for each  
portion of the unlock. Once the first portion of the  
password unlock completes (RDY is not driven and  
DQ6 does not toggle when read), the Password Un-  
lock command is issued again, only this time with the  
next part of the password. Four Password Unlock com-  
mands are required to successfully clear the PPB  
Lock Bit. As with the first Password Unlock command,  
the RDY signal goes LOW and reading the device re-  
sults in the DQ6 pin toggling on successive read oper-  
ations until complete. It is the responsibility of the  
microprocessor to keep track of the number of Pass-  
word Unlock commands, the order, and when to read  
the PPB Lock bit to confirm successful password un-  
lock. In order to relock the device into the Password  
Mode, the PPB Lock Bit Set command can be re-is-  
sued. Exiting the Password Unlock Command is ac-  
complished by writing SecSi Sector Exit command.  
DYB Write Command  
The DYB Write command is used to set or clear a DYB  
for a given sector. The high order address bits  
(Amax–A11) are issued at the same time as the code  
01h or 00h on DQ7-DQ0. All other DQ data bus pins  
are ignored during the data write cycle. The DYBs are  
modifiable at any time, regardless of the state of the  
PPB or PPB Lock Bit. The DYBs are cleared at  
power-up or hardware reset. Exiting the DYB Write  
May 10, 2006 27024B3  
Am29BDS128H/Am29BDS640H  
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