CS4231A Datasheet, PDF (61/76 Pages) List of Unclassifed Manufacturers – PARALLEL INTERFACE MULTIMEDIA AUDIO CODEC

CDB4231/4248
SOFTWARE COMPATIBILITY
The CDB4231/4248 comes with two sets of soft-
ware: diagnostics and Windows 3.1 drivers. The
diagnostics will support all hardware jumper set-
tings. The Windows software will support all
hardware settings when configured for generic
hardware. When the included Windows software
(or any software) is configured or designed for
100% Windows Sound System compatibility,
limitations in the hardware selections exist.
The CDB4231/4248 evaluation board includes a
board ID PLD, ID31, that indicates to software
that the board is Windows Sound System, WSS,
compatible. This read-only register is located at
the first four addresses (the second four are for
the codec). This ID will read back 0x04 from the
lower six bits. Although the evaluation board is
WSS compatible from the codec register per-
spective, the auto-select hardware of the WSS
board is not included. The DMA and IRQ set-
tings must be configured via on-board jumpers.
The four base addresses supported by the evalu-
ation board are the same as specified for WSS
hardware.
Windows software, such as the included drivers
and applets, that check for a WSS board will
read the board ID and assume that the auto-se-
lect register needs to be loaded. The auto-select
register only allows certain combinations which
must be adhered to when using the evaluation
board with this software.
Therefore, to run 100% compatible Windows
Sound System, WSS, software, the IRQ and
DMA selection must be made from the follow-
ing:
INT: 7
10
11
(default)
Half Duplex: DMA PLAY:
0
1
3 (CDB4248 default)
DMA CAPTURE:
No jumpers (CDB4248 default)
Full Duplex: PLAY CAPTURE
0
1
1
0 (CDB4231 default)
3
0
Note in full duplex, only the three combinations
listed are allowed with the last combination be-
ing the default for the CDB4231. If the software
does not support full duplex, remove the jumpers
on the DMA CAPTURE header, J1 (Figure 7).
The Crystal Windows software provided with the
evaluation board can be configured for 100%
WSS compatible hardware and will load the
Auto-Select register with the proper DMA and
IRQ settings. In 100% WSS mode, the Crystal
software will not allow improper settings for the
DMA and IRQ.
Some hardware, including the CDB4231/4248,
allow selection of DMA and IRQ via on-board
jumpers. These jumpers allow a wider selection
of configuration options since it is not limited by
the Auto-Select register options listed above.
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