BL7432SM Low voltage Intelligent 2K bits
EEPROM
Function Description
Block Diagram
M a in
m e m o ry
P ro te c tio n
m e m o ry
255
EEPROM
256X8
32
31
0
A d d res s
31
Area for
perma nent
da ta stora ge
0
A d d ress
D a ta
D a ta
8
M e m o ry
M ain /P rotection
S ecu rity
5
H V G e n e ra to r
C u rre n t
G e n e ra to r
D e co d e r
C olu m n
S a m p lin g
A d d . D a ta
R e g is te r
,
C o m p a ra to r
P ro g ra m
C o n tro l
R eset
B lock Logi
c
L o g ic
S e q ue nc e r
A nd
S e c urity
In terfac e
VCC
GND
I/O R S T C L K
Figure 2
The BL7432SM consists of 256 x 8 bit EEPROM main memory (figure 2) and a 32-bit
protection-memory with PROM functionality .The main memory is erased and written byte by
byte. When erased, all 8 bits of a data byte are set to logical one. When written, the information in
the individual EEPROM cells is to the input data, altered bit by bit to logical zeros (logical AND
between the old and the new data in the EEPROM).
Normally a data change consists of an erase and write procedure. It depends on the
contents of the data byte in the main memory and the new data byte whether the EEPROM is
really erased and/or written. If none of the 8 bits in the addressed byte requires a zero-to-one
transition the erase access will be suppressed. Vice versa the write access will be suppressed if
no one-to-zero transition is necessary. The write and the erase operation takes at least 2.5 ms
each. The first 32 bytes can be irreversibly protected against data change by writing the
corresponding bit in the protection memory. Each data byte in this address range is assigned to
one bit of the protection memory and has the same address as the data byte in the main memory
which it is assigned to. Once written the protection bit cannot be erased.
Transmission Protocol
The transmission protocol is a two wire link protocol between the interface device IFD and
the integrated circuit IC. It is identical to the protocol type “S=10”. All data changes on I/O are
initiated by the falling edge on CLK.
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Total
8 Pages
5/18/2010
Wrote by ICCD
BELLING [ SHANGHAI BELLING CO., LTD. ]
