X9110

FN8158 Rev 5.00

Page 5 of 18

October 28, 2016

At both ends of each array and between each resistor segment is

individual array only one switch may be turned on at a time.

These switches are controlled by a Wiper Counter Register

(WCR). The 10-bits of the WCR (WCR[9:0]) are decoded to select,

and enable, one of 1024 switches.

WIPER COUNTER REGISTER (WCR)

The X9110 contains a Wiper Counter Register (see Table 1) for

the XDCP potentiometer. The WCR is equivalent to a serial-in,

parallel-out register/counter with its outputs decoded to select

one of 1024 switches along its resistor array. The content of the

WCR can be altered in one of three ways: (1) it may be written

directly by the host via the write Wiper Counter Register

instruction (serial load); (2) it may be written indirectly by

transferring the content of one of four associated Data Registers

via the XFR Data Register; (3) it is loaded with the content of its

data register zero (DR0) upon power-up.

The Wiper Counter Register is a volatile register; that is, its content is

lost when the X9110 is powered-down. Although the register is

automatically loaded with the value in DR0 upon power-up, this

may be different from the value present at power-down.

Power-up guidelines are recommended to ensure proper

loadings of the DR0 value into the WCR.

DATA REGISTERS (DR)

The potentiometer has four 10-bit nonvolatile Data Registers.

These can be read or written directly by the host. Data can also

be transferred between any of the four Data Registers and the

Wiper Counter Register. All operations changing data in one of

the Data Registers is a nonvolatile operation and will take a

maximum of 10ms.

If the application does not require storage of multiple settings for

the potentiometer, the Data Registers can be used as regular

memory locations for system parameters or user preference

data.

DR[9:0] is used to store one of the 1024 wiper position (0~1023)

(see Table 2).

STATUS REGISTER (SR)

This 1-bit status register is used to store the system status (see

Table 3).

WIP: Write In Progress status bit, read only.

• When WIP = 1, indicates that high-voltage write cycle is in

progress.

• When WIP = 0, indicates that no high-voltage write cycle is in

progress.

TABLE 3. STATUS REGISTER, SR (1-BIT)

TABLE 4. IDENTIFICATION BYTE FORMAT

TABLE 1. WIPER CONTROL REGISTER, WCR (10-BIT), WCR9–WCR0: Used to store the current wiper position (Volatile, V)

WCR9

WCR8

WCR7

WCR6

WCR5

WCR4

WCR3

WCR2

WCR1

WCR0

VVVVVVVVVV

(MSB)

(LSB)

TABLE 2. DATA REGISTER, DR (10-BIT), BIT 9–BIT 0: Used to store wiper positions or data (Nonvolatile, NV)

BIT 9BIT 8BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0

NV

NV

NV

NV

NV

NV

NV

NV

NV

NV

(MSB)

(LSB)

WIP

(LSB)

ID3

ID2

ID1

ID0

0

0

A0

R/W

0101

(MSB)

(LSB)

DEVICE TYPE

IDENTIFIER

INTERNAL SLAVE

ADDRESS

READ OR

WRITE BIT