X76F041
10
Random Read without Password
Random read operations without a password do not
require the first byte block initiation address. To perform a
random read without password, a START is followed by
the read command plus address location of the byte to
be read. This is followed by an “ACK” and the eight bits of
data to be read. Other bytes within the same 1K-bit block
may be read by issuing another START followed by a
new 8-bit address as shown in figure 9.
Sequential Read
Once past the password acceptance sequence (when
required) and “secure read setup”, the host can read
sequentially within the originally addressed 1K-bit array.
The data output is sequential, with the data from address
n followed by the data from address n+1. The address
counter for read operations increments the address,
allowing the 1K memory contents to be serially read dur-
ing one operation. At the end of the address space
(address 127), the counter “rolls over” to address space 0
within the 1K Block and the X76F041 continues to output
data for each acknowledge received. Refer to figure 10
for the address, acknowledge and data transfer
sequence. An acknowledge must follow each 8-bit data
transfer. After the last bit has been read, a stop condition
is generated without a preceding acknowledge.
Figure 9. Random Read without Password
Figure 10. Sequential Read with Password
S
T
A
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C M D A
X
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X
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8
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SDA LINE
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0
DATA 0
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7002 ILL F13A.2
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DATA 1
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C M D A
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READ
PASSWORD 7
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A
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READ
PASSWORD 0
WAIT
tWC/ACK POLLING
SECURE
READ SETUP
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SDA LINE
IF PASSWORD
MATCH THEN
DATA X
DATA 0
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K
7002 ILL F12.3
A
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DATA 1
X X X X X X X X
FIRST BYTE
BLOCK ADDRESS