DP7401 datasheet(8/15 Pages) COPAL

8 / 15 page

DP7401

Doc. No. MD-2012 Rev. H

Characteristics subject to change without notice

Wiper Control and Data Registers

Wiper Control Register (WCR)

The DP7401 contains four 6-bit Wiper Control

Registers, one for each potentiometer. The Wiper

Control Register output is decoded to select one of 64

switches along its resistor array. The contents of the

WCR can be altered in four ways: it may be written by

the host via Write Wiper Control Register instruction; it

may be written by transferring the contents of one of

four associated Data Registers via the XFR Data

time by the Increment/decrement instruction (see

Instruction section for more details). Finally, it is

loaded with the content of its data register zero (DR0)

upon power-up.

The Wiper Control Register is a volatile register that

loses its contents when the DP7401 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.

Data Registers (DR)

Each potentiometer has four 6-bit non-volatile 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 associated Wiper Control

Registers is a non-volatile operation and will take a

maximum of 5ms.

Write in Process

The contents of the Data Registers are saved to

nonvolatile memory when the CS

¯¯¯ input goes HIGH

after a write sequence is received. The status of the

internal write cycle can be monitored by issuing a

Read Status command to read the Write in Process

(WIP) bit.

Instructions

Four of the nine instructions are three bytes in length.

These instructions are:

— Read Wiper Control Register – read the current

wiper position of the selected potentiometer in the

WCR

— Write Wiper Control Register – change current

wiper position in the WCR of the selected

potentiometer

— Read Data Register – read the contents of the

selected Data Register

— Write Data Register – write a new value to the

selected Data Register

— Read Status – Read the status of the WIP bit

which when set to "1" signifies a write cycle is in

progress.

Table 3. Instruction Set

Note: 1/0 = data is one or zero

Instruction Set

Instruction

WCR1/ P1

WCR0/ P0

Operation

Read Wiper Control

1/0

Read the contents of the Wiper Control

Write Wiper Control

1/0

Write new value to the Wiper Control

Read Data Register

1/0

Read the contents of the Data Register

pointed to by P1-P0 and R1-R0

Write Data Register

1/0

Write new value to the Data Register

pointed to by P1-P0 and R1-R0

XFR Data Register to

Wiper Control Register

1/0

Transfer the contents of the Data Register

pointed to by P1-P0 and R1-R0 to its

associated Wiper Control Register

XFR Wiper Control

1/0

Transfer the contents of the Wiper Control

Global XFR Data

Registers to Wiper

Control Registers

1/0

Transfer the contents of the Data Registers

pointed to by R1-R0 of all four pots to their

respective Wiper Control Registers

Global XFR Wiper

Control Registers to

Data Register

1/0

Transfer the contents of both Wiper Control

Registers to their respective data Registers

pointed to by R1-R0 of all four pots

Increment/Decrement

Wiper Control Register

1/0

Enable Increment/decrement of the Control

Latch pointed to by P1-P0

Read Status (WIP bit)

101

Read WIP bit to check internal write cycle

status

DP7401 Datasheet(PDF) 8 Page - Copal Electronics

DP7401 Datasheet(HTML) 8 Page - Copal Electronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Datasheet Download

Link URL