X76F041 Datasheet, PDF (10/21 Pages) Xicor Inc. – PASS TM SecureFlash

X76F041
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.
Figure 9. Random Read without Password
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.
SDA LINE
S
T
A
R
T
C
M
D
A
X
A
X
A
X
A
X
A
8
AAAAAAAA
76543210
S
A
A
C
C
K
K
DATA 0
S
T
A
RA ^{A A A AA A A}
T7 ^{6 5 4 32 1 0}
S
A
C
K
DATA 1
S
T
O
P
S
7002 ILL F13A.2
Figure 10. Sequential Read with Password
SDA LINE
FIRST BYTE
S
BLOCK ADDRESS
T
A
R
T
C
M
D
A
X
A
X
A
X
A
X
A
8
AAAAAAAA
76543210
READ
PASSWORD 7
S
A
A
A
C
C
C
K
K
K
IF PASSWORD
MATCH THEN
SECURE
READ SETUP
S
T
A
R
T
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
XXXXXXXXS
DATA 0
A
A
A
C
C
C
K
K
K
READ
PASSWORD 0
WAIT
tWC/ACK POLLING
A
A
C
C
K
K
DATA 1
S
T
DATA X _O
P
S
7002 ILL F12.3
10