BL7448SM データシートの表示（PDF） - Shanghai Belling Co., Ltd.
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BL7448SM Datasheet PDF : 7 Pages
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BL7448SM Intelligent 8K-bit
EEPROM
0 1234 5 670 12 345 67 012 3456
S0 S1 S2 S3 S4 S5 A8 A9 A0 A1 A2 A3 A4 A5 A6 A7 D0 D1 D2 D3 D4 D5 D6 D7
Bute 1
Bute 2
Bute 3
Control Byte
Address
Data
Figure 4 Command Input
Command Mode
Write/Erase Operation
Write/Erase, except for protection-memory
Note: Write means from H to L, Erase means from L to H
There are three kinds of Write/Erase operations:
Erase and Write (The number of clock pulses=203, frequency <=20KHZ)
Write only: means the 8 bits in the addressed byte from H to L( The number of clock pulses =103,
frequency <=20KHZ)
Erase only(=FF; The number of clock pulses =103, frequency <= 20KHZ)
Write/Erase, include protection-memory
As shipped, the protection-memory has been erased, it can be written only once.
Write protection-memory and compare data
When comparison of the entered data byte is same as the assigned byte in the EEPROM. the
protection-memory is written.
After sent a certain CLK, the command of Write/Erase will be over. After operation, the state of I/O pin
will be changed from H to L.
The I/O state can be changed when RST change from L to H.
Command Input
Processing
RES
CLK
0
E/W
Internal signal
23 0 1 2
99
102
TE
TW
199
202
I/O S0 S1 D6 D7
Command Input
RES
CLK
0
23 0 1 2
E/W
Internal signal
Figure 5 Erase and Write timing
Processing
99
102
TE
TW
199
202
I/O S0 S1 D6 D7
Figure 6 Only Write or Erase
Read operation
Read main memory (See Figure 7)
This operation don’t read the protection-memory. After 8 CLK, the address of memory will be increased
by additional pulse .
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Total 7 Pages
8/16/2006
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