CS4237B Datasheet, PDF (12/114 Pages) Cirrus Logic – CrystalClear Advanced Audio System with 3D Sound

CS4237B
GENERAL DESCRIPTION
This device is comprised of six physical devices
along with Plug-and-Play support for two addi-
tional external devices. The internal devices are:
Windows Sound System Codec
Sound Blaster Pro Compatible Interface
Game Port (Joystick)
Control
MPU-401
FM Synthesizer
The two external devices are:
IDE CDROM
Modem
A full ISA interface with Plug and Play compati-
bility and an External Peripheral Port for
interfacing to external devices (i.e. Wave-Table
Synthesizer, CDROM, and Modem) is included.
Since the Wave-Table Synthesizer and CDROM
analog inputs are external, mapping as shown in
Figure 5, on page 58, must be used to maintain
Sound Blaster compatibility, i.e. CDROM analog
must be connected to the AUX2 analog inputs of
the mixer.
On power up, this part requires a RESDRV sig-
nal to initialize the internal configuration. When
initially powered up, the part is isolated from the
bus, and each device supported by the part must
be activated via software. Once activated, each
device responds to the resources given (Address,
IRQ, and DMA channels). The eight devices
listed above are grouped into six logical devices,
as shown in Figure 1 (bracketed features are sup-
ported, but typically not used). The six logical
devices are:
LOGICAL DEVICE 0:
Windows Sound System Codec (WSS Codec)
Adlib/Sound Blaster-compatible Synthesizer
Sound Blaster Pro Compatible Interface
LOGICAL DEVICE 1: Game Port
LOGICAL DEVICE 2: Control
LOGICAL DEVICE 3: MPU401
LOGICAL DEVICE 4: CDROM
LOGICAL DEVICE 5: Modem
Logical Device 0 consists of three physical de-
vices. The WSS Codec and the Synthesizer are
grouped together since the original Windows
Sound System board expected an FM synthesizer
if the codec was present. The Sound Blaster Pro
Compatible interface, SBPro, is also grouped to
allow the WSS Codec and the SBPro to share
Interrupts and DMA channels. The Synthesizer
device could be the internal FM synthesizer, or a
synthesizer externally located on the Peripheral
Port. The external synthesizer interface supports
both FM and wavetable synthesizers such as the
CS9233. The WSS Codec, FM synthesizer, and
the SBPro compatible devices are internal to the
part.
Logical Device 1 is the Game Port that supports
up to two joystick devices.
Logical Device 2 is the Control device that sup-
ports global features of the part. This device uses
I/O locations to control power management,
joystick rate, and PnP resource data loading.
Logical Device 3 is the MPU-401 interface. The
MPU-401 MIDI interface includes a 16-byte
FIFO for data transmitted out the MIDOUT pin
and a 16-byte FIFO for data received from the
MIDIN pin.
Logical Device 4 supports an IDE CDROM con-
nected to the peripheral port. This interface, on
the external peripheral port, can support
CDROMs with up to 8 I/O locations and sup-
ports both the base address and the alternate base
address, an interrupt, and a DMA channel. Al-
though this logical device is listed as a CDROM,
any external device that fits within the resources
listed above may be substituted.
12
DS213PP4