Overview; Cs8415A An Cs8405A; Parallel Port; Serial Digital Inputs - Cirrus Logic Crystal CDB8415A Manual

1. OVERVIEW

The CDB8415A evaluation board contains a
CS8415A and a CS8405A and the supporting cir-
cuitry necessary for them to operate. The input and
output options include AES3 and S/PDIF in optical
and coaxial formats. In software mode, the control
registers of the CS8415A and CS8405A are set
through the parallel port of a PC by a Windows 98
based program to control the configuration.
1.1

CS8415A an CS8405A

The features and functions of the CS8415A and the
CS8405A are described in their data sheets.
1.2

Parallel Port

To use the CS8415 A and CS8405A on the board in
software mode, the parallel port on the upper right
hand side of the board should be connected to the
parallel port of the PC running the CDB8415A con-
trol software. In software mode remember to en-
able the clocks in both parts from the configuration
software.
1.3

Serial Digital Inputs

The left hand end of the board is occupied by a row
of serial digital audio input connectors. In hardware
mode, the user may select from the optical connec-
tor, the XLR connector, or the first RCA jack. Only
one of these inputs should be connected at a time.
In software mode the user has access to these inputs
and to the S/PDIF multiplexer. In the multiplexer
mode jack J17, labeled OPT, should be jumpered in
the enable position. The user can provide inputs to
any or all of the seven RCA input jacks. The active
input is selected by setting the three least signifi-
cant bits of Control Register 2. Please note that
the current version of the board has a layout er-
ror. Jacks 6 and 7 are reversed.
1.4

Serial Digital Outputs

On the upper right hand side of the board are the
three serial digital audio outputs. The Optical
S/PDIF output is always enabled. The user may
DS470DB1
also choose to enable either the coaxial S/PDIF out-
put or the XLR AES3 output.
1.5

Three Wire Serial Input and Output

Jacks J32 and J51 are provided so the user may ac-
cess the three wire serial ports of the receiver and
transmitter. The purpose of these ports is to allow
the user to connect his external circuitry to the re-
ceiver and transmitter. A flat jumper cable is also
provided to allow the output of the receiver to drive
the input of the transmitter. This allows the user to
operate the board in transceiver mode.
1.6

Micro-Controller Serial Ports

Headers J6 and J37 provide access to the serial con-
trol ports of the CS8415A and the CS8405A. Each
jack has four serial control lines, a reset line, and an
interrupt line. This allows the user to connect an ex-
ternal MCU of his choice to carry out testing and
software development. These ports are in the same
format as the header on the CDB8420 or the
CDB8427. These two boards use an Atmel AVR
microcontroller that can be patched in to communi-
cate with the parts on this board. Another alterna-
tive is to patch in the development board of the
MCU of your choice.
1.7

Crystal Oscillators

Oscillator U7 provides the Output Master Clock
for the CS8405A. The crystal oscillator on the
board is mounted in pin sockets that allow it to be
removed or replaced. The board is shipped with a
12.288 MHz crystal oscillator stuffed at U7 which
sets the output sampling rate to 48 kHz.
1.8

LED Function Indicators

LEDs D3 and D4 on the middle left hand side of the
board allow the user to monitor the receiver status.
LED D4 is connected to the RERR pin of the
CS8415A and LED3 is connected to NVERR. See
the CS8415A data sheet for an explanation of the
errors that activate each of these outputs.
CDB8415A
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