AD7877

Rev. A | Page 39 of 44

Register Name: DAC Register

Write Address: 1110; Read Address: 01110; Default Value: 0x000.

Table 21.

Bit

Name

Read/

Write

Description

0

RANGE

R/W

Output range of the DAC in voltage mode

1

Not Used

R/W

This bit is not used.

2

V/I

R/W

Voltage output and current output

0 = Voltage

1 = Current

3

PD

R/W

DAC power-down

0 = DAC on

1 = DAC powered down

4

DAC0

LSB of DAC data

5

DAC1

Bit 1 of DAC data

6

DAC2

Bit 2 of DAC data

7

DAC3

Bit 3 of DAC data

8

DAC4

Bit 4 of DAC data

9

DAC5

Bit 5 of DAC data

10

DAC6

Bit 6 of DAC data

11

DAC7

MSB of DAC data

Register Name: Y Position

Write Address: N/A; Read Address: 10000; Default Value: 0x000; Type: Read Only.

This register contains the 12-bit result of the measurement at the X+ input with Y layer excited (Y position measurement).

Register Name: X Position

Write Address: N/A; Read Address: 10001; Default Value: 0x000; Type: Read Only.

This register contains the 12-bit result of the measurement at the Y+ input with X layer excited (X position measurement).

Register Name: Z2

Write Address: N/A; Read Address: 10010; Default Value: 0x000; Type: Read Only.

This register contains the 12-bit result of the measurement at the Y− input with excitation voltage applied to Y+ and X− (used for touch-

pressure calculation).

Register Name: AUX1

Write Address: N/A; Read Address: 10011; Default Value: 0x000; Type: Read Only.

This register continues the 12-bit result of the measurement at Auxiliary Input 1.

Register Name: AUX2

Write Address: N/A; Read Address: 10100; Default Value: 0x000; Type: Read Only.

This register continues the 12-bit result of the measurement at Auxiliary Input 2.

Register Name: AUX3

Write Address: N/A; Read Address: 10101; Default Value: 0x000; Type: Read Only.

This register continues the 12-bit result of the measurement at Auxiliary Input 3.