X40420 XICOR [Xicor Inc.], X40420 Datasheet - Page 7

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

X40420/X40421 – Preliminary
Figure 6. V
WEL: Write Enable Latch (Volatile)
The WEL bit controls the access to the memory and to
the Register during a write operation. This bit is a vola-
tile latch that powers up in the LOW (disabled) state.
While the WEL bit is LOW, writes to any address,
including any control registers will be ignored (no
acknowledge will be issued after the Data Byte). The
WEL bit is set by writing a “1” to the WEL bit and
zeroes to the other bits of the control register.
REV 1.2.14 7/12/02
Old V
TRIPX
New V
X
applied + | Error |
Set/Reset Sequence (X = 1, 2)
X
applied =
Error < MDE
NO
–
No
V
Set Higher V
Set V
> Desired V
Apply V
V
TRIPX
TRIPX
Output Switches?
Desired V
Actual V
Present Value
X
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Decrease V
= desired V
V
Reset Sequence
Desired
Execute
Execute
CC
DONE
TRIPX
Programming
and Voltage
TRIPX
X
TRIPX -
| Error | < | MDE |
TRIPX
Sequence
YES
YES
<
to V
X
TRIPX
Once set, WEL remains set until either it is reset to 0
(by writing a “0” to the WEL bit and zeroes to the other
bits of the control register) or until the part powers up
again. Writes to the WEL bit do not cause a high volt-
age write cycle, so the device is ready for the next
operation immediately after the stop condition.
X
Error > MDE
Old V
Execute Reset V
Characteristics subject to change without notice.
New V
X
Sequence
applied - | Error |
+
Let: MDE = Maximum Desired Error
Vx = V
Note: X = 1, 2
X
applied =
Desired Value
CC
TRIPX
, VxMON
MDE
MDE
Error = Actual - Desired
+
–
Error Range
Acceptable
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