BL7442LV 데이터 시트보기 (PDF) - Shanghai Belling Co., Ltd.
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BL7442LV Datasheet PDF : 10 Pages
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BL7442LV Low voltage
Intelligent 2K bits EEPROM
Commands
(1) Command Format
Each command consists of three byte:
MSB Control
LSB MSB Address
LSB
B7 B6 B5 B4 B3 B2 B1 B0 A7 A6 A5 A4 A3 A2 A1 A0
Beginning with the control byte LSB is transmitted first.
Byte 1 Control
Byte 2
Address
Byte 3
Data
B7 B6 B5 B4 B3 B2 B1 B0 A7~A0
D7~D0
0 0 1 1 0 0 0 0 Address
No effect
0 0 1 1 1 0 0 0 Address
Input data
0 0 1 1 0 1 0 0 No effect
No effect
0 0 1 1 1 1 0 0 Address
Input data
0 0 1 1 0 0 0 1 No effect
No effect
0 0 1 1 1 0 0 1 Address
Input data
0 0 1 1 0 0 1 1 Address
Input data
MSB Data
LSB
D7 D6 D5 D4 D3 D2 D1 D0
Operation
Mode
Read Main
Memory
Update
Main Memory
Read Protection
Memory
Write Procection
Memory
Read Security
Memory*
Update Security
Memory*
Compare
Verification
Data*
Outgoing data
Processing
Outgoing Data
Processing
Outgoing Data
Processing
Processing
(2) Description of Command
Read Main Memory
The command reads out the contents of the main memory(with LSB first)starting at the given byte
address(N) UP TO THE END MEMORY. After the command entry the IFD has to supply sufficient
clock pulses. The number of clocks is m=(256-N)*8+1.The read access to the main memory is
always possible.
Read Protection Memory
The command transfers the protection bits under a continuous input of 32 clock pulses to the
output. I/O is switched to state H by an additional pulse. The protection memory can always be
read.
Read Security Memory
Similar to the read command for the protection memory this command reads out the 4 bytes of
the security memory. The number of clock pulses during the outgoing data mode is 32.I/O is
switched to state H by an additional pulse. Without a preceeding successful verification of the
PSC the output of the reference bytes is suppressed, that means I/O remains in state L.
Update Main Memory
The command programs the address EEPROM byte with the data byte transmitted. Depending
on the old and new data, one of the following sequences will take place during the processing
mode:
-- erase and write
(5ms) corresponding to m = 255 clock pulses
-- write without erase (2.5ms) corresponding to m = 124 clock pulses
-- erase without write (2.5ms) corresponding to m =124 clock pulses
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Total 10 Pages
8/16/2006
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