u-blox LARA-R203 System Integration Manual page 118

Examples of manufacturers offering compatible audio codec parts are the following:

Maxim Integrated (as the MAX9860, MAX9867, MAX9880A audio codecs)

Texas Instruments / National Semiconductor

Cirrus Logic / Wolfson Microelectronics

Nuvoton Technology

Asahi Kasei Microdevices

Realtek Semiconductor
Figure 65 and Table 48 describe an application circuit for the I
capability using an external audio voice codec, in particular the Maxim MAX9860 audio codec.

DAC and ADC integrated in the external audio codec respectively converts an incoming digital data stream to
analog audio output through a mono amplifier and converts the microphone input signal to the digital bit
stream over the digital audio interface,

A digital side-tone mixer integrated in the external audio codec provides loopback of the microphones/ADC
signal to the DAC/headphone output.

The module's I 2 S interface (I

The GPIO6 of the LARA-R2 series module (that provides a suitable digital output clock) is connected to the
clock input of the external audio codec to provide clock reference.

The external audio codec is controlled by the LARA-R2 series module using the DDC (I
concurrently communicate with other I

The V_INT output supplies the external audio codec, defining proper digital interfaces voltage level.

Additional components are provided for EMC and ESD immunity conformity: a 10 nF bypass capacitor and a
series chip ferrite bead noise/EMI suppression filter provided on each microphone line input and speaker line
output of the external codec as described in Figure 65 and Table 48. The necessity of these or other additional
parts for EMC improvement may depend on the specific application board design.
Specific AT commands are available to configure the Maxim MAX9860 audio codec: for more details, see the
u-blox AT Commands Manual [2], +UEXTDCONF AT command.
As various external audio codecs other than the one described in Figure 65 and Table 48 can be used to provide
voice capability, the appropriate specific application circuit must be implemented and configured according to the
particular external digital audio device or audio codec used and according to the application requirements.
LARA-R2 series
(except LARA-R204-02B and LARA-R220-62B)
Figure 65: I 2 S interface application circuit with an external audio codec to provide voice capability
UBX-16010573 - R12
2 S master) is connected to the related pins of the external audio codec (I
2
C devices and control an external audio codec.
V_INT
4
R1 R2 R3
SDA
26
SCL
27
I2S_TXD
35
I2S_RXD
37
I2S_CLK
36
I2S_WA
34
GPIO6
19
GND
LARA-R2 series - System Integration Manual
2
S digital audio interface providing basic voice
1V8
Audio
Codec
C1 C2
VDD
IRQn MICBIAS
C4
R4
SDA
SCL
MICLP
C5
MICLN
SDIN
C6
SDOUT
R5
BCLK MICGND
LRCLK
EMI3
OUTP
EMI4
MCLK
OUTN
GND
U1
2
C) interface, which can
C3
Microphone
EMI1
EMI2
C12 C11
C8 C7
D1
C14 C13 C10 C9
D2
Page 118 of 157
2 S slave).
Connector MIC
J1
SPK
Speaker
Connector
J2
Design-in