Texas Instruments PCM1681, Руководство пользователя

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SBAU137 – April 2008
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Description
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Basic Connection and Operation
1.3 Basic Connection and Operation
• Set/confirm jumper JP001 to provide the system clock and other digital signals from the digital audio
receiver to the PCM1681.
•
Set/confirm jumper JP201–JP224 to select the cutoff frequency of the second-order post low-pass filter
(LPF) for DAC outputs.
• Set/confirm jumper HDR002 and HDR001 of the PCM1681 daughtercard to select mode control and
coressponding primary pin function.
•
Connect the +5-V and
±
15-V power supplies to V
CC
, AV
CC
, –AV
CC
, and GND on connectors
CN051–CN055.
• Connect the S/PDIF signal into CN001 (COAX) or U001 (OPT).
• Connect the PC printer port to CN003 for mode control, if required.
• Set/confirm the input data format using SW001–SW003 and SW006 (H/W control mode) or the
demonstration software (S/W SPI control).
1.4 EVM Configuration Controls
1.4.1 Jumper Controls
The following jumpers are provided onboard for configuration controls:
• JP001: Set Interface of Digital Signal from DIR to DAC (the device under test [DUT])
The digital signal generated by the digital interface receiver (DIR) is input to this jumper. For each
shorted pin, the corresponding digital signal is applied to the PCM1681. All signals except for BCK and
BCK [L/J] must be shorted for normal operation using the DIR; for BCK and BCK [L/J], one or the other
must be shorted according to the data format selection of the DIR. Figure 1-2 shows jumper JP001.
JP001
SCLK
CLKO
GND
BCK
BCK [L/J]
LRCK
DATA1
DATA2
DATA3
DATA4
Figure 1-2. Jumper JP001
•
JP201–JP224 (24 Pieces):
Set f
C
(Corner Frequency) Selection of Second-Order Post LPF
These jumpers determine the corner frequency (f
C
) of the second-order post low-pass filter.
– JP201–JP224 shorted: f
C
= 54 kHz for BW = 20 kHz
– JP201–JP224 open: f
C
= 108 kHz for BW = 40 kHz