- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄374140 > CAT33C804A 4K-Bit Secure Access Serial E2PROM PDF資料下載
參數(shù)資料
| 型號(hào)： | CAT33C804A |
| 英文描述： | 4K-Bit Secure Access Serial E2PROM |
| 中文描述： | 4K的位安全接入串行E2PROM |
| 文件頁(yè)數(shù)： | 4/14頁(yè) |
| 文件大?。?/td> | 89K |
| 代理商： | CAT33C804A |
第1頁(yè)第2頁(yè)第3頁(yè)當(dāng)前第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)第11頁(yè)第12頁(yè)第13頁(yè)第14頁(yè)
Preliminary
CAT33C804A
4
Doc. No. 25044-00 2/98
PASSWORD PROTECTION
The CAT33C804A is a 4K-bit E
2
PROM that features a
password protection scheme to prevent unauthorized
access to the information stored in the device. It contains
an access code register which stores one to eight bytes
of access code along with the length of that access code.
Additionally, a memory pointer register stores the ad-
dress that partitions the memory into protected and
unprotected areas. As shipped from the factory, the
device is unprogrammed and unprotected. The length of
the access code is equal to zero and the memory pointer
register points to location zero. Every byte of the device
is fully accessible without an access code. Setting a
password and moving the memory pointer register to
cover all or part of the memory secures the device. Once
secured, the memory is divided into a read/write area
and a read-only area with the entry of a valid access
code. If no access code is entered, the memory is
divided into a read-only area and a non-access area.
Figure 2 illlustrates this partitioning of the memory array.
WRITE PROTECTION
Another feature of the CAT33C804A is WRITE-protec-
tion without the use of an access code. If the memory
pointer register is set to cover all or part of the memory,
without setting the access code register, the device may
be divided into an area which allows full access, and an
area which allows READ-only access. To write into the
READ-only area, the user can override the memory
pointer register for every WRITE instruction or he can
simply move the address in the memory pointer register
to uncover this area, and then write into the memory.
This mechanism prevents inadvertent overwriting of
important data in the memory without the use of an
access code. Figure 3 illustrates this partitioning of the
memory array.
Figure 1. A.C. Timing
Note:
(1) If PE pin = 1.
33C804 F03
VCC
CS
CLK
DI
tVCCS
DO
tD
HIGH-Z
START BIT
tD
STOP BIT
HIGH-Z
tHZ
DATA TIMING
MARK
SPACE
BIT TIME
104
μ
s
S
B
S
B
P
B
(1)
D0
D1
D2
D3
D4
D5
D6
D7
CHARACTER TIME @ 9600 BAUD
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| CAT33C804AJ-TE13 | 4K-Bit Secure Access Serial E2PROM |
| CAT33C804AJA-TE13 | 4K-Bit Secure Access Serial E2PROM |
| CAT33C804AJI-TE13 | 4K-Bit Secure Access Serial E2PROM |
| CAT33C804AP-TE13 | 4K-Bit Secure Access Serial E2PROM |
| CAT33C804APA-TE13 | 4K-Bit Secure Access Serial E2PROM |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| CAT33C804ACI | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Serial EEPROM |
| CAT33C804ADI | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Serial EEPROM |
| CAT33C804AJATE13 | 制造商:CATALYST 制造商全稱:Catalyst Semiconductor 功能描述:4K-Bit Secure Access Serial E2PROM |
| CAT33C804AJA-TE13 | 制造商:CATALYST 制造商全稱:Catalyst Semiconductor 功能描述:4K-Bit Secure Access Serial E2PROM |
| CAT33C804AJITE13 | 制造商:CATALYST 制造商全稱:Catalyst Semiconductor 功能描述:4K-Bit Secure Access Serial E2PROM |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。