AD7156

Rev. 0 | Page 20 of 28

CONFIGURATION REGISTER

Address Pointer 0x0F

8 Bits, Read/Write, Factory Preset 0x19

Table 12. Configuration Register Bit Map1

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

ThrFixed

ThrMD1

ThrMD0

EnCh1

EnCh2

MD2

MD1

MD0

(0)

(0)

(0)

(1)

(1)

(0)

(0)

(1)

Table 13.Configuration Register Bit Descriptions

Bit

Mnemonic

Description

7

ThrFixed

ThrFixed = 1 sets the fixed threshold mode; the outputs reflect the comparison of data and a fixed (constant)

value of the threshold registers.

ThrFixed = 0 sets the adaptive threshold mode; the outputs reflect the comparison of data to the adaptive

thresholds. The adaptive threshold is set dynamically, based on the history of the previous data.

6

5

ThrMD1

ThrMD0

These bits set the output comparators mode

ThrMD1

ThrMD0

Threshold Mode

Output Active When

Adaptive Threshold Mode

Fixed Threshold Mode

0

0

Negative

Data < average – sensitivity

Data < threshold

0

1

Positive

Data > average + sensitivity

Data > threshold

1

0

In-window

Data > average – sensitivity

and

Data < average + sensitivity

1

1

Out-window

Data < average – sensitivity

or

Data > average + sensitivity

4

EnCh1

Enables conversion on Channel 1

3

EnCh2

Enables conversion on Channel 2

2

1

0

MD2

MD1

MD0

Converter mode of operation setup

MD2

MD1

MD0

Mode

Description

0

0

0

Idle

The part is fully powered up, but performing no conversion.

0

0

1

Continuous

Conversion

The part is repeatedly performing conversions on the

enabled channel(s); if two channels are enabled, the part is

sequentially switching between them.

0

1

0

Single conversion

The part performs a single conversion on the enabled

channel; if two channels are enabled, the part performs two

conversions, one on each channel. After finishing the

conversion(s), the part goes to the idle mode.

0

1

1

Power-down

The part powers down the on-chip circuits, except the

digital interface.

1

X

X

Reserved

Do not use these modes.