User guide

Si471x-EVB
10 Preliminary Rev. 0.4
3.2.4. Audio I/O
Figure 11. Audio I/O Block Diagram
The EVB for the Si471x Alpha 3 supports three different kinds of configurations:
1. Analog to Analog
2. Analog to Digital
3. Digital to Digital
Analog to Analog: This configuration provides a way for the user to evaluate the Si471x analog audio input for FM
transmission.
The input to the EVB is an analog audio provided via the RCA input connector J7 or LINE In connector J19 (white).
Jumpers J5 and J13 are set to RCA input by default. The user has to change this jumper accordingly if LINE In is
being used. Then the analog audio input is routed directly through a switch to the Si471x Rin/Lin inputs pin 15 and
16 (Audio2).
Analog to Digital: This configuration provides a way for the user to evaluate the Si471x digital audio input for FM
Transmission using an analog audio input.
The input to the EVB is an analog audio provided via the RCA input connector J7 or LINE In connector J19 (white).
Jumpers J5 and J13 are set to RCA input by default. The user has to change this jumper accordingly if LINE In is
being used. Then the analog audio input is converted by CODEC U10 to a serial audio digital data before it is
routed to the Si471x digital audio input DIO and DFS pin 13 and 14 (Audio1). The DCLK input is routed to the
GPO3/DCLK pin 17. Make sure that jumper J41 is set to DCLK to ensure proper operation.
Digital to Digital: This configuration provides a way for the user to evaluate the Si471x digital audio input for FM
Transmission using an S/PDIF digital audio commonly found in sound cards.
The input to the EVB is a digital S/PDIF data provided via the S/PDIF In connector J19 (white). The digital S/PDIF
input is converted by S/PDIF Translator U9 to a serial audio digital data before it is routed to the Si471x digital
audio input DIO and DFS pin 13 and 14 (Audio1). The DCLK input is routed to the GPO3/DCLK pin 17. Make sure
that jumper J41 is set to DCLK to ensure proper operation.
Jumper
J5&J13
EVB In 471x Audio2 471x Audio1 EVB Out
1
0
0
1
CODEC OUT
DIN
LINE
OUT
CODEC IN
LINE
IN
DOUT
S/PDIF IN
SPDIF
IN
DOUT
S/PDIF OUT
DIN
SPDIF
OUT
0
1
0
1
Jumper
J45
Analog/Digital Analog Digital N/A
AUDIO2
To_TX
From_RX
AUDIO1
From_RX
To_TX
Jumper
J44
RCA In
Line In
(white)
SPDIF In
(white)
RCA Out
Line Out
(black)
SPDIF Out
(black)
SI471x
(daughter board)
LIN
RIN
DFS1
DIO1
14
13
AUDIO1:
Digital TX
AUDIO2:
Analog TX
15
16
J7
J19
J19
J6
J30
J30
Audio2
Select
Audio1
Select
Digital Input
Select
Note: Jumper J44 and J45 are automatically configured in EVB Rev 1.3.