X40420 XICOR [Xicor Inc.], X40420 Datasheet - Page 14

• Manufacturer Part Number: X40420
• Description: Dual Voltage Monitor with Integrated CPU Supervisor and System Battery Switch
• Manufacturer: XICOR [Xicor Inc.]

Word Address
The word address is either supplied by the master or
obtained from an internal counter.
Operational Notes
The device powers-up in the following state:
– The device is in the low power standby state.
– The WEL bit is set to ‘0’. In this state it is not possible
– SDA pin is the input mode.
– RESET/RESET Signal is active for
Figure 17. Sequential Read Sequence
X40420/X40421 – Preliminary
Figure 15. Random Address Read Sequence
Figure 16. X40410/11 Addressing
REV 1.2.14 7/12/02
General Purpose Memory
Control Register
Fault Detection Register
General Purpose Memory
Control Register
Fault Detection Register
to write to the device.
Signals from
Signals from
the Master
the Slave
SDA Bus
Signals from
Signals from
the Master
the Slave
SDA Bus
Word Address
Slave Byte
A7
1
1
1
1
1
Address
A6 A5 A4
Slave
0
0
0
1
1
S
a
t
r
t
1
1 0 1
1
1
1
1
1
C
A
K
Address
0
1
1
Slave
1
1
t
PURST
0
A3 A2
0
0
0
0
1
1
Data
(1)
0
0
0
0
1
1
.
C
A
K
A8 R/W
1
0
A1 A0
1
1
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R/W
R/W
Address
A
C
K
1
1
Byte
Data
(2)
Data Protection
The following circuitry has been included to prevent
inadvertent writes:
– The WEL bit must be set to allow write operations.
– The proper clock count and bit sequence is required
– A three step sequence is required before writing into
– The WP pin, when held HIGH, prevents all writes to
prior to the stop bit in order to start a nonvolatile write
cycle.
the Control Register to change Watchdog Timer or
Block Lock settings.
the array and all the Register.
A
C
K
S
a
r
t
t
Address
A
C
K
Slave
(n is any integer greater than 1)
Characteristics subject to change without notice.
Data
(n-1)
1
A
C
K
Data
C
A
K
Data
(n)
S
o
p
t
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S
o
p
t