EVAL-AD5144DBZ View Datasheet(PDF) - Analog Devices

Part Name

Description

MFG CO.

EVAL-AD5144DBZ

Quad Channel, 128-/256-Position, I2C/SPI, Nonvolatile Digital Potentiometer

Analog Devices 

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AD5124/AD5144/AD5144A

Data Sheet

Daisy-Chain Connection

Daisy chaining minimizes the number of port pins required from

the controlling IC. As shown in Figure 44, the SDO pin of one

package must be tied to the SDI pin of the next package. The clock

period may need to be increased because of the propagation

delay of the line between subsequent devices. When two AD5124/

AD5144 devices are daisy chained, 32 bits of data are required.

The first 16 bits are assigned to U2, and the second 16 bits are

assigned to U1, as shown in Figure 45. Keep the SYNC pin low

until all 32 bits are clocked into their respective serial registers.

The SYNC pin is then pulled high to complete the operation.

To prevent data from mislocking (for example, due to noise) the

part includes an internal counter, if the SCLK falling edges count is

not a multiple of 8, the part ignores the command. A valid clock

count is 16, 24, 32, 40, and so on. The counter resets when SYNC

returns high.

MOSI

MICROCONTROLLER

MISO SCLK SS

VLOGIC

AD5124/

AD5144

SDI U1 SDO

RP

2.2kΩ

VLOGIC

AD5124/

AD5144

SDI U2 SDO

RP

2.2kΩ

SYNC SCLK

SYNC SCLK

SCLK

SYNC

MOSI

SDO_U1

Figure 44. Daisy-Chain Configuration

1

2

16

17

18

32

DB15

DB15

INPUT WORD FOR U2

DB0 DB15

INPUT WORD FOR U1

DB0

DB0 DB15

DB0

UNDEFINED

INPUT WORD FOR U2

Figure 45. Daisy-Chain Diagram

Rev. C | Page 24 of 36

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