ISL22429 Datasheet, PDF (11/13 Pages) Intersil Corporation – Low Noise, Low Power, SPI Bus, 128 Taps, Wiper Only

ISL22449
CS
SCK
SDI
0 1 0 1 0 0 0 0 0 I3 I2 I1 I0 R3 R2 R1 R0
0 D6 D5 D4 D3 D2 D1 D0
FIGURE 12. THREE BYTE WRITE SEQUENCE
CS
SCK
SDI
DON’T CARE
0 1 0 1 0 0 0 0 0 I3 I2 I1 I0 R3 R2 R1 R0
SDO
0 D6 D5 D4 D3 D2 D1 D0
FIGURE 13. THREE BYTE READ SEQUENCE
Applications Information
Communicating with ISL22449
Communication with ISL22449 proceeds using SPI interface
through the ACR (address 1000b), IVRi (addresses 0000b,
0001b, 0010b and 0011b) and WRi (addresses 0000b,
0001b, 0010b and 0011b) registers.
The wiper of the potentiometer is controlled by the WRi
register. Writes and reads can be made directly to these
registers to control and monitor the wiper position without
any non-volatile memory changes. This is done by setting
MSB bit at address 1000b to 1.
The non-volatile IVRi stores the power up value of the wiper.
IVRs are accessible when MSB bit at address 1000b is set
to 0. Writing a new value to the IVRi register will set a new
power up position for the wiper. Also, writing to this register
will load the same value into the corresponding WRi as the
IVRi. Reading from the IVRi will not change the WRi, if its
contents are different.
11
FN6333.3
July 17, 2009