S9418 Datasheet, PDF (3/10 Pages) Summit Microelectronics, Inc. – Quad 8-Bit Nonvolatile DACPOT™ Electronic Potentiometer With a Mute Control Input

S9418
S CH CL AH AL
1 0 0 A A NV Enable - Data Don’t Care
1 0 1 A A Write Command - Data In
1 1 0 A A Read - Data Out
1 1 1 A A Recall -Data Don’t Care
TABLE 1. COMMAND FORMAT
2023 PGM T1 1.0
Internally there are four DACs and associated with each
are two registers. There is one data register that is used
by the DAC to hold the digital value it converts. There is
also one nonvolatile register that holds the default value
that can be recalled into the data register during power-
up or by executing the Recall command.
READ
Read operations are initiated by taking CS LOW and
clocking in a start bit followed by the read command and
the address of the data register to be read. The next eight
clocks will output on the DO pin the contents of the
selected data register. This read will not affect the con-
tents of the register or the output of the DAC. Refer to
Figure 1 for an illustration of the sequence of bus condi-
tions for a read operation.
WRITE
Write operations are initiated by taking CS LOW and
clocking in a start bit followed by the write command and
the address of the data register to be written. This action
is followed by the host clocking eight bits of data into the
register, MSB first. The output of the selected DAC will
change as the last bit is clocked into the device. At this
point the clock counter will reset the command register,
requiring a full sequence to be initiated in order to write to
the DAC again. NOTE: This write operation does not
affect the contents of the nonvolatile register. Therefore,
the nonvolatile register can contain the power-on default
settings (e.g. volume), and the write DAC command can
be used to make situational adjustments. Refer to Figure
2 for an illustration of the sequence of bus conditions for
a write operation.
CS
CLK
DI
DO
RDY/BSY
S
T
C1 C0 A1 A0
A
R
T
Hi Z
D7 D6 D5 D4 D3 D2 D1 D0
Hi Z
Pulled Up to VDD
2023 ILL3 1.0
FIGURE 1. READ SEQUENCE
2023 1.5 4/24/99
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