User's Manual

www.rovingnetworks.com Version 1.1 3/19/13 page 6
Advanced Information
RN52-DS
1.1 Audio Interface Circuit
Description
The RN52 audio interface circuit consists of:
• Stereo audio CODEC
• Dual audio inputs and dual outputs
• Configurable S/PDIF and I
2
S interface
The audio input circuitry has a dual audio input that can
be configured as single-ended or fully differential and
programmed for microphone or line input. It has an
analog and digital programmable gain stage so that it
can be optimized for different microphones. See
Figure 1-4.
1.1.1 STEREO AUDIO CODEC
INTERFACE
The stereo audio CODEC interface has stereo and
mono analog input/output for voice and audio bands. It
supports the IEC-60958 stereo digital audio bus stan-
dards, e.g., S/PDIF and AES3/EBU.
The built-in CODEC uses a fully differential architecture
in the analog signal path, which results in low noise
sensitivity and good power supply rejection while effec-
tively doubling the signal amplitude. It operates from a
1.5 V single power supply and uses a minimum of
external components. See Figure 1-5.
27 GND Ground. Ground.
28 SPI_SS CMOS input with weak
internal pull-up.
Chip select for Synchronous Serial Interface
active low.
Input
29 SPI_MISO CMOS output, tri-state, with
weak internal pull-down.
Serial Peripheral Interface (SPI) output. Output
30 SPI_CLK Input with weak internal
pull-down.
SPI clock. Input
31 SPI_MOSI CMOS input, with weak
internal pull-down.
SPI input. Input
32 LED1 Open drain output. Drives an LED. For the RN-52-EK board, this
signal drives the red LED.
Output
33 LED0 Open drain output. Drives an LED. For the RN-52-EK board, this
signal drives the blue LED.
Output
34 MIC_BIAS Analog. Microphone bias. Output
35 MIC_L+ Analog. Microphone input positive, left. Output
36 MIC_R+ Analog. Microphone input positive, right. Output
37 MIC_L- Analog. Microphone input negative, left. Output
38 MIC_R- Analog. Microphone input negative, right. Output
39 AGND Analog. Ground connection for audio.
40 SPK_R- Analog. Speaker output negative (right side). Output
41 SPK_L- Analog. Speaker output negative (left side). Output
42 SPK_R+ Analog. Speaker output positive (right side). Output
43 SPK_L+ Analog. Speaker output positive (left side). Output
44 GND Ground. Ground.
45 GND Ground. RF ground.
46 GND Ground. RF ground.
47 GND Ground. RF ground.
48 GND Ground. RF ground.
49 GND Ground. RF ground.
50 GND Ground. RF ground.
Note 1: All GPIO pins default to input with weak pull-down.
TABLE 1-4: PIN DESCRIPTION (PART 3 OF 3) Note 1
Pin Symbol I/O Type Description Direction Default