Datasheet

1-6 SHARC Audio EZ-Extender Manual
The audio interface connections are shown in Figure 2-2; more details can
be found in “SHARC Audio EZ-Extender Schematic” on page B-1. The
three codec chips (referred to as “AD1939A”, “AD1939B”, and
“AD1939C”) connect in parallel to the serial peripheral interface (SPI)
port of the ADSP-21469 SHARC processor via the DPI pins. The SPI
port of the processor is used to adjust volume and other audio parameters
of each of the three codecs.
The serial ports (SPORTs) are used to transmit and receive audio data to
and from the processor via the DAI pins. The analog audio channels are
available via single-ended RCA connectors (
J2—7) or differential DB25
connectors (P1—5). By default, the extender is shipped with the RCA con-
nectors used by the AD1939 codecs for audio in and out. P1—5 are used to
switch to differential mode. A standard, off the shelf DB25 connector to
XLR cables is required to operate in differential mode. The P1—5 connec-
tors require five XLR cables for full functionality. The XLR cables are not
provided with the EZ-Extender. The mating cable’s manufacturer and
part number information can be found in “Differential In/Out Connec-
tors (P1–5)” on page 2-18.
The DAI pins of the master codec can be configured to transfer serial data
from the codec in Time-Division Multiplexing (TDM) mode or Inte-
grated Interchip Sound (I
2
S) mode. The master input clock (MCLK) of the
codec is generated by the on-board 12.288 MHz oscillator. The internal
PLL of the codec is used to generate varying sample rates. The codec can
be set up for 48 KHz, 96 KHz, or 192 KHz frequencies. The master codec
(codec A) can run at these frequencies in both TDM and I
2
S modes with
all ADCs inputs and DACs outputs. Codecs B and C are wired on the
EZ-Extender and allow TDM mode operations only.
• At a 48 kHz sample rate, TDM mode allows up to 16 channels of
data to be sent from each chip in each direction. Each chip uses
four of the 16 input channels and eight of the 16 output channels.