X40231 Datasheet, PDF (12/36 Pages) Intersil Corporation – Triple Voltage Monitors, POR, 2 kbit EEPROM MEMORY, and Single/Dual DCP

X40231, X40233, X40235, X40237, X40239
V_CC
V_{CC (Max.)}
V_TRIP1
t_TRANS
t_PURST
t
0
Maximum Wiper Recall time
Figure 7. DCP Power-up
A nonvolatile write to a DCP will change the “wiper posi-
tion” by simultaneously writing new data to the associ-
ated WCR and NVM. Therefore, the new “wiper position”
setting is recalled into the WCR after V_CC of the X4023x
is powered down and then powered back up.
A volatile write operation to a DCP however, changes
the “wiper position” by writing new data to the associ-
ated WCR only. The contents of the associated NVM
register remains unchanged. Therefore, when V_CC to
the device is powered down then back up, the “wiper
position” reverts to that last position written to the DCP
using a nonvolatile write operation.
Both volatile and nonvolatile write operations are exe-
cuted using a three byte command sequence: (DCP)
Slave Address Byte, Instruction Byte, followed by a
Data Byte (See Figure 9)
A DCP Read operation allows the user to “read out”
the current “wiper position” of the DCP, as stored in
the associated WCR. This operation is executed using
the Random Address Read command sequence, con-
sisting of the (DCP) Slave Address Byte followed by
an Instruction Byte and the Slave Address Byte again
(Refer to Figure 10).
Instruction Byte
While the Slave Address Byte is used to select the
DCP devices, an Instruction Byte is used to determine
which DCP is being addressed.
The Instruction Byte (Figure 8) is valid only when the
Device Type Identifier and the Internal Device Address
bits of the Slave Address are set to 1010111. In this
case, the two Least Significant Bit’s (I1 - I0) of the
Instruction Byte are used to select the particular DCP
(0 - 2). In the case of a Write to any of the DCPs (i.e.
I7 I6 I5 I4 I3 I2 I1 I0
WT 0 0 0 0 0 P1 P0
WRITE TYPE
DCP SELECT
WT^†
Description
0
Select a Volatile Write operation to be performed
on the DCP pointed to by bits P1 and P0
1
Select a Nonvolatile Write operation to be per-
formed on the DCP pointed to by bits P1 and P0
†_{This bit has no effect when a Read operation is being performed.}
Figure 8. Instruction Byte Format
the LSB of the Slave Address is 0), the Most Signifi-
cant Bit of the Instruction Byte (I7), determines the
Write Type (WT) performed.
If WT is “1”, then a Nonvolatile Write to the DCP occurs.
In this case, the “wiper position” of the DCP is changed
by simultaneously writing new data to the associated
WCR and NVM. Therefore, the new “wiper position”
setting is recalled into the WCR after V_CC of the X4023x
has been powered down then powered back up.
If WT is “0” then a DCP Volatile Write is performed.
This operation changes the DCP “wiper position” by
writing new data to the associated WCR only. The
contents of the associated NVM register remains
unchanged. Therefore, when V_CC to the device is
powered down then back up, the “wiper position”
reverts to that last written to the DCP using a nonvol-
atile write operation.
12
FN8115.0
April 11, 2005