X76F041
12
Configuration of Passwords
The sequence in figure 14 will change (program) the
write, read and configuration passwords. The program-
ming of passwords is done twice prior to the nonvolatile
write cycle in order to verify that the new password is
consistent. After the eight bytes are entered in the sec-
ond pass, a comparison takes place. A mismatch will
cause the part to reset and enter into the standby mode
and a “no ACK” will be issued.
There is no way to read the Read/Write/Configuration
passwords.
Program Configuration Registers
This mode allows programming of the five configuration/
control registers using the configuration password. The
retry counter must be programmed with a value less than
the retry register. If it is programmed with a value larger
than the retry register there will be a wrap around.
Read Configuration Registers
This mode allows reading of the 5 configuration/control
registers with the configuration password. It may be use-
ful for monitoring purposes.
Figure 13. Configuration Random Read
Figure 14. Program Passwords
S
T
A
R
T
S
C M D A
X
A
X
A
X
A
X
A
8
A
C
K
CONFIGURATION
PASSWORD 7
A
C
K
A
C
K
A
C
K
A
C
K
CONFIGURATION
PASSWORD 0
WAIT
tWC/ACK POLLING
SECURE
READ SETUP
A
C
K
S
T
A
R
T
SDA LINE
IF PASSWORD
MATCH THEN
S
A
C
K
7002 ILL F16.3
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
FIRST BYTE
BLOCK ADDRESS
DATA 0
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
S
T
A
R
T
S
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
A
C
K
DATA 1
S
T
O
P
S
X X X X X X X X
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T
A
R
T
S
C M D A
X
A
X
A
X
A
X
A
8
A
C
K
OLD
PASSWORD 7
A
C
K
A
C
K
A
C
K
OLD
PASSWORD 0
WAIT
tWC/ACK POLLING
NEW
PASSWORD 7
A
C
K
A
C
K
SDA LINE
IF PASSWORD
MATCH THEN
NEW
PASSWORD 7
NEW
PASSWORD 0
A
C
K
A
C
K
READ/WRITE/
CONFIGURATION
INSTRUCTION
S
T
O
P
S
NEW
PASSWORD 0
WAIT
tWC
A
C
K
A
C
K
7002 ILL F17.1