AD7151 Просмотр технического описания (PDF) - Analog Devices

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AD7151

Ultra-Low Power, 1-Channel, Capacitance Converter for Proximity Sensing

Analog Devices 

AD7151

POWER-DOWN TIMER REGISTER

Address Pointer 0x10

8 Bits, Read/Write, Factory Preset 0x00

Table 14. Power-Down Timer Register Bit Map

Bit

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Mnemonic

–

–

Power-Down Timeout (6-Bit Value)

Default

0

0

0x00

Table 15. Power-Down Timer Register Bit Descriptions

Bit Mnemonic

Description

[7:6] -

These bits must be 0 for proper operation

[5:0] Power-Down

Timeout

Defines the period duration of the power-down timeout.

If the output comparator output has not been activated during the programmed period, the part enters power-

down mode automatically. The part can be then returned to a normal operational mode either via the serial

interface or by the power supply off/on sequence.

The period is programmable in steps of four hours. For example, setting the value to 0x06 sets the duration to

24 hours. The maximum value of 0x3F corresponds to approximately 10.5 days.

The value of 0x00 disables the power-down timeout, and the part does not enter power-down mode

automatically.

CAPDAC REGISTER

Address Pointer 0x11

8 Bits, Read/Write, Factory Preset 0x00

Table 16. CAPDAC Register Bit Map

Bit

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Mnemonic

DacEn

DacAuto

DacValue (6-Bit Value)

Default

1

1

0x00

Table 17. CAPDAC Register Bit Descriptions

Bit Mnemonic

Description

7

DacEn

DacEn = 1 enables capacitive DAC.

6

DacAuto

DacAuto = 1 enables the AutoDAC function in the adaptive threshold mode.

When the AutoDAC function is enabled, the part dynamically adjusts the CAPDAC to keep the CDC in an

optimal operating capacitive range. The CAPDAC value is automatically incremented when the data average

exceeds ¾ of the CDC full range, and the CAPDAC value is decremented when the data average goes below ¼

of the CDC full range. The AutoDAC increment or decrement step depends on the selected CDC capacitive

input range.

Bit has no effect in fixed threshold mode; the AutoDAC function is always disabled in the fixed threshold mode.

[5:0] DacValue

CAPDAC value, Code 0x00 ≈ 0 pF, Code 0x3F ≈ CAPDAC full range.

SERIAL NUMBER REGISTER

Address Pointer 0x13, 0x14, 0x15, 0x16

32 Bits, Read Only, 0xXXXX

This register holds a serial number, unique for each individual part.

CHIP ID REGISTER

Address Pointer 0x17

8 Bits, Read Only, 0xXX

This register holds the chip identification code, used in factory

manufacturing and testing.

Rev. 0 | Page 20 of 28

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