BL7448SM 데이터 시트보기 (PDF) - Shanghai Belling Co., Ltd.
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BL7448SM Datasheet PDF : 7 Pages
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BL7448SM Intelligent 8K-bit
EEPROM
Read main memory and protection-memory (See Figure 8)
After input this command, the next 8 CLK will read out 8 bits data; the ninth CLK will read out the
content of protection-memory. After 9 CLK, the address of memory will be increased by additional
pulse.
Security code verification
Byte1
Byte2
Address
Byte3
Address
Operation
0 1 0 0 1 1 1 1 253
Write error
Bit mask
counter
Verification 1st
1 0 1 1 0 0 1 1 254 PSC byte1
PSC byte
Verification 2nd
1 0 1 1 0 0 1 1 255 PSC byte2
PSC byte
Mode
Processing
Processing
Processing
Command
Input
RST
CLK
Data Output
I/O
A8 A9
D6 D7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
Starting Address
random
value
Starting Address
Starting Address + 1
Figure 7 Read main memory
Starting Address + n
Command Input
RST
Data
Output
CLK 0
23
I/O
A8 A9
D6 D7 0 1 2 3 4 5 6 7 P0 0 1 2 3 4 5 6 7 P0 P0 0 1 2 3 4 5 6 7 P0
Starting Address
random
value
Starting Address
Starting Address +1
Starting Address + n
Figure 8 read main memory and protection-memory
Security code verification
User verification operation
BL7448SM only can read when the security code verification is unsuccessful. The content of security code
cannot be read out. If you try to read security code, you only can get “00”
The processing is:
*Write a bit of EC(the bit is not written before), the address of EC is “1021”
*Input the first byte of PSC, the address is “1022”
*Input the second byte of PSC, the address is “1023”
*If the security verification is successful , the EC can be erased.
http://www.belling.com.cn
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Total 7 Pages
8/16/2006
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