CDB5378 datasheet(42/72 Pages) CIRRUS

42 / 72 page

CDB5378

DS639DB3

3.3.5

Gain / Offset

The Gain / Offset sub-panel controls the digital filter GAIN and OFFSET registers.

The OFFSET and GAIN registers can be manually written with any 24-bit 2’s complement value from

0x800000 to 0x7FFFFF. The USEGR, USEOR, ORCAL, and EXP[4:0] values enable gain correction, off-

set correction, and offset calibration in the digital filter.

The offset calibration routine built into the digital filter is enabled by writing the ORCAL and EXP[4:0] bits.

The EXP[4:0] value can range from 0x00 to 0x18 and represents an exponential shift of the calibration

feedback, as described in the digital filter data sheet. Offset calibration results are automatically written to

the OFFSET registers and remain there, even after offset calibration is disabled.

Control

Description

Gain

Displays the digital filter GAIN register.

Offset

Displays the digital filter OFFSET register.

Read

Reads values from the GAIN and OFFSET registers.

Write

Writes values to the GAIN and OFFSET registers.

USEGR

Enables gain correction. When enabled, output samples are gained down by the

value in the GAIN register.(Output = GAIN / 0x7FFFFF).

USEOR

Enables offset correction. When enabled, output samples are offset by the value in

the OFFSET register. (Output = Sample - OFFSET).

ORCAL

Enables offset calibration using the exponent value from the EXP[4:0] control.

Results are automatically written to the OFFSET registers as they are calculated.

EXP[4:0]

Sets the exponential value used by offset calibration.

CDB5378 Datasheet(PDF) 42 Page - Cirrus Logic