Creative SB0350 Hardware Programming Guide - Page 62

Creative SB0350 Manual

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4-4 Mixer Chip Programming CT1335 Mixer This section describes the features and register functions of the CT1335 mixer chip used on the Sound Blaster 2.0 CD Interface card. Features CT1335 is a mono mixer chip that only controls the output mixing. It has the following features: Volume Control CT1335 provides independent 8-level volume control for the Master, MIDI and CD sources. The Voice source has 4-levels of volume control. Output Mixing The output mixing path takes signals from the Voice, MIDI and CD, as well as the PC Speaker. To silence a source, you can either reduce the source volume to zero or terminate the source activity. Register Functions The following notations are used to describe the detailed register map of CT1335: „ „ Index 0x00 0x02 0x06 0x08 0x0A "0xRR" represents the mixer register number in hexadecimal. The grayed areas of the table represent reserved bits. D6 D5 D4 D3 D2 Master volume MIDI volume CD volume Voice volume D7 D1 D0 Reset Mixer Figure 4-1: Register Map of CT1335 Mixer

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4-4
Mixer Chip Programming
CT1335 Mixer
This section describes the features and register functions of the CT1335 mixer chip
used on the Sound Blaster 2.0 CD Interface card.
Features
CT1335 is a mono mixer chip that only controls the output mixing.
It has the
following features:
Volume Control
CT1335 provides independent 8-level volume control for the
Master
,
MIDI
and
CD
sources.
The
Voice
source has 4-levels of volume control.
Output Mixing
The output mixing path takes signals from the
Voice
,
MIDI
and
CD
, as well as the
PC Speaker
.
To silence a source, you can either reduce the source volume to zero or
terminate the source activity.
Register Functions
The following notations are used to describe the detailed register map of CT1335:
±
"0x
RR
" represents the mixer register number in hexadecimal.
±
The grayed areas of the table represent reserved bits.
Index
D7
D6
D5
D4
D3
D2
D1
D0
0x00
Reset Mixer
0x02
Master volume
0x06
MIDI volume
0x08
CD volume
0x0A
Voice volume
Figure 4-1: Register Map of CT1335 Mixer