MAX9867 Просмотр технического описания (PDF) - Maxim Integrated

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MAX9867

Ultra-Low Power Stereo Audio Codec

Maxim Integrated 

Ultra-Low Power Stereo Audio Codec

Complete DC Measurement Example

MCLK = 13MHz, slave mode, BCLK and LRCLK not

externally supplied:

1) Configure the digital audio interface for fS = 48kHz

(PSCLK = 01, FREQ = 0x0, PLL = 0, NI = 0x5ABE,

MAS = 0).

2) Disable JACKSNS (JDETEN = 0).

3) Enable the left and right ADC; take the MAX9867 out

of shutdown (ADLEN = ADREN = SHDN = 1).

4) Calibrate the offset:

a. Enable the AUX input (AUXEN = 1).

b. Enable the offset calibration (AUXCAL = 1).

c. Wait 40ms.

d. Complete calibration (AUXCAL = 0).

5) Calibrate the gain:

a. Start gain calibration (AUXGAIN = 1).

b. Wait 40ms.

c. Freeze the measurement results (AUXCAP = 1).

d. Read AUX and store the value in memory to cor-

rect all future measurements (k = AUX[15:0]).

e. Complete calibration (AUXGAIN = AUXCAP =

AUXEN = 0).

6) Measure the voltage on JACKSNS/AUX:

a. Enable the AUX input (AUXEN = 1).

b. Wait 40ms.

c. Freeze the measurement results (AUXCAP = 1).

d. Read AUX and correct with the gain calibration

value.

e. Complete measurement (AUXCAP = 0).

7) DC measurement complete.

Table 14. ADC Input Register

REGISTER

ADC Input

B7

B6

MXINL

B5

B4

MXINR

B3

B2

B1

AUXCAP AUXGAIN AUXCAL

B0

AUXEN

REGISTER

ADDRESS

0x14

BITS

MXINL/MXINR

AUXCAP

AUXGAIN

AUXCAL

AUXEN

FUNCTION

Left/Right ADC Audio Input Mixer

00 = No input is selected.

01 = Left/right analog microphone

10 = Left/right line input

11 = Left/right analog microphone + line input

Note: If the right-line input is disabled, then the left-line input is connected to both mixers. Enabling the

left and right digital microphones disables the left and right audio mixers, respectively. See DIGMICL/

DIGMICR in Table 15 for more details.

Auxiliary Input Capture

0 = Update AUX with the voltage at JACKSNS/AUX.

1 = Hold AUX for reading.

Auxiliary Input Gain Calibration

0 = Normal operation

1 = The input buffer is disconnected from JACKSNS/AUX and connected to an internal voltage reference.

While in this mode, read the AUX register and store the value. Use the stored value as a gain

calibration factor, K, on subsequent readings.

Auxiliary Input Offset Calibration

0 = Normal operation

1 = JACKSNS/AUX is disconnected from the input and the ADC automatically calibrates out any internal

offsets.

Auxiliary Input Enable

0 = Use JACKSNS/AUX for jack detection.

1 = Use JACKSNS/AUX for DC measurements.

Note: For AUXEN = 1, set MXINR = 00, ADLEN = 1, and ADREN = 1.

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