Cirrus Logic CDB4244 - Manual (Page 4)

4 DS900DB2
CDB4244
1 SYSTEM OVERVIEW
The CDB4244 platform provides analog and digital interfaces to the CS4244 and allows for external DSP and I²C
TM
control. Board configuration can be done using the Windows PC-compatible graphical user interface (GUI) to read
and write device registers. Multiple analog input and output filter configurations are supported, as well are several
different options for generating a system master clock.
The CDB4244 schematic set has been partitioned into eight pages and is shown in Section 8 starting on page 23 .
Additionally, Section 6 on page 20 provides a description of all external connectors, including the default factory set-
tings for all jumpers.
1.1 Power
Power is supplied to the board through an external regulated +5-V supply or a PC USB port. The CS4244
analog supply (referred to as VA) may be taken from the selected +5-V supply or an onboard +3.3-V regu-
lator.
Table 4 on page 21 explains how to configure each option. A dual-rail ±12-V regulated supply is re-
quired to power the active filter network used for each analog input channel. A special resistor option allows
the optional active analog output filter configurations to use either a single-rail or dual-rail power supply.
Shunt jumpers and 1%, 1-
Ω parallel resistors provide a convenient way to measure both the VA and VL
supply currents to the CS4244. The current is easily calculated by measuring the voltage drop across each
resistor with its associated shunt removed. The shunts connected in parallel with these resistors must be in
place during normal operation.
WARNING: Please refer to the CS4244 data sheet for allowable voltage levels.
1.2 Grounding and Power Supply Decoupling
The CS4244 requires careful attention to power supply and grounding arrangements to optimize perfor-
mance. The CDB4244 demonstrates these optimal arrangements.
Figure 18 on page 31 shows the compo-
nent placement; Figure 19 on page 32 shows the top-side layout and Figure 22 on page 35 shows the
bottom-side layout. Power supply decoupling capacitors are located as close as possible to the CS4244.
Extensive use of ground plane fill helps reduce radiated noise.
1.3 CS4244 Multi-Channel CODEC
A complete description of the CS4244 ( Figure 10 on page 23 ) can be found in the CS4244 data sheet. The
CS4244 is configured using the Cirrus Logic FlexGUI software. The device configuration registers are ac-
cessible via the “Register Maps” tab of the software. This tab provides low-level control of each bit in the
device’s control port. The “CODEC Control” and “Volume Control” tabs provide high-level control of the de-
vice for faster configuration. See
Section 2 on page 7 for details.
1.4 CS8406 Digital Audio Transmitter
The CS8406 S/PDIF transmitter ( Figure 11 on page 24 ) converts the digital audio generated by the CS4244
(I²S or Left-Justified serial interface formats) to the standard S/PDIF data stream and routes these signals
to the optical and RCA connectors on the CDB4244. With a supplied master clock, the CS8406 can master
the serial audio interface timing for the CDB4244.
The CS8406 can be controlled using the Cirrus Logic FlexGUI software under the “Board Control” tab. See
Section 2.1 on page 8 for details. A complete description of the CS8406 and a discussion of the digital audio
interface can be found in the CS8406 data sheet.