2.5
ADC Interface
2.6
Board Power up General Guidelines
3
Jumpers and Control Utilities
3.1
Clock Frequency Change Jumper
3.2
SPDIF/PSIA Utilization Jumpers
3.3
Data Routing Jumpers
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Jumpers and Control Utilities
In the absence of digital signal source ADC (PCM1808) may be used to convert an analog audio signal to
digital signal and provide it to TAS5704. DIR9001 still provides clocks to ADC in this process. The
frequency of the oscillator selected for DIR 9001determinse the sampling frequency in the absence of
digital signal. If the OSC is 24MHz the sampling frequency will be set at 96kHz and if the OSC is selected
to be 12MHz the sampling frequency will be defaulted to 48kHz when there is no signal on SPDIF input
terminals. ADC is an additional feature to this board to provide flexibility in sourcing audio signal to
TAS5704. Please review the datasheet of PCM1808 for detail description of the ADC on this EVM.
After connecting the loud speakers (loads), power supply, and data line, power up the VIN power supply.
Then power up the PVCC power supply. It is recommended to set the PVCC level to 10 volts and then
ramp it up to 20 volts to verify the cable connection functionality. It is recommended to set the gain to
–3dB at start by having both GAIN (
GAIN0
and
GAIN1
) jumpers inserted. Note that the gain settings
marked on the EVM are not correct. Please see
Table 3
on the next page for the correct settings. Having
jumpers
FM0
and
FM1
inserted and FM2 removed sets the data format for the device to I2S format. Make
sure the SPDIF format jumpers,
FMT0
and
FMT1
are removed to set the receiver format to I2S. It is
important to note that a device RESET (S2 on the top of the board labeled
MASTER RESET
) needs to be
applied after each gain, format, or configuration change in order for the device to latch in the new settings.
Finally, install jumpers CFG1 and
CFG2
in the Config Control to select
2-CH-BTL-AD
mode.
JP1: In the presence of a valid digital signal input, when SPDIF lock occurs, the user may use JP1 to
change LR clock and BIT clock. When a shunt is inserted, the SCKO = 512Fs and when the shunt is
removed the SCKO = 256Fs. Default is SCKO = 256Fs.
In the absence of a valid digital signal DIR9001 clock outputs switch to the frequency of crystal (Y1). If the
crystal is chosen to be 24MHz the LR clock will be 96KHz and if the crystal is chosen to be 12MHz the LR
clock will be 48kHz.
The jumpers MCLK, LRCK, SCLK, SDATA allow the user to switch between the internal clock and data
sources and external clock and data sources for instance PSIA (from AP instrument). The default
configuration of these jumpers is SPDIF as it is marked on the EVM with a white arrow. PSIA outputs may
be utilized using pins 2 and 3 of the jumpers. Keep in mind that pin 3 of each jumper is connected to
GND. Thus, the user must pay attention to the polarity of the PSIA output cables at the time of insertion.
Jumpers SDIN1, SDIN2: These jumpers enable the user to assign a data source to TAS5704 SDIN1 and
SDIN2 pins. See
Table 2
.
Table 2. TAS5704 SDINx Data Source
Jumper JP15:SDIN1
Jumper JP16:SDIN2
SDIN1 Source
SDIN2 Source
Position
Position
1-2
1-2
ADC
ADC
1-2
2-3
SPDIF/PSIA
SPDIF/PSIA
2-3
1-2
SPDIF/PSIA
ADC
2-3
2-3
SPDIF/PSIA
SPDIF/PSIA
SLOU224 – April 2008
TA5704EVM 4-Channel Digital Audio Power Amplifier with Hardware Control
11
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