Specifications

20 SAM0023-122898 ESS Technology, Inc.
ES1869 DATA SHEET
PERIPHERAL INTERFACING
Figure 9 Telegaming Mode
Telegaming Mode
This mode is enabled when two conditions are present:
1. The DSP serial port must be enabled (i.e., either bit 7
of mixer register 48h is high or the input pin SE is high).
2. Bit 1 of mixer register 48h is high. This bit enables
Telegaming mode.
In previous chips, when the DSP serial port is enabled, the
Audio 1 CODEC is unavailable for use by the first audio
channel. This means digital audio for Sound Blaster Pro
compatible games is muted. Sound Blaster can use only
the first audio channel for digital audio. The Audio 1
CODEC is used by the DSP.
In Telegaming mode, the first audio channel can be
switched over to the Audio 2 DAC. Internally, the first audio
channel is routed to the second audio channel DAC and
the second audio channel has no function. In addition, the
second audio channel mixer volume control is slaved to
the first channel mixer volume control.
Default Mode
The default mode operates just like Telegaming mode
except that data from the first audio channel cannot be
heard. Data sent through the second audio channel can be
mixed as in Telegaming mode.
Figure 10 Default Mode
No Acoustic Echo Cancellation
The DSP cannot perform acoustic echo cancellation in
either mode. Because the audio from the host does not
pass directly through the DSP, there is no way for the DSP
to compensate for acoustic echo. Therefore, using a
headset for either the microphone or speakers or both is
recommended.
DSP Digital Audio Playback
There are two choices for mixing the DSP digital audio
playback data with other audio sources. The audio data
can be mixed in the ES1869’s internal playback mixer or
externally to the ES1869.
Mixing Internal to the ES1869
The DSP digital audio playback can be mixed within the
ES1869 playback mixer. To select this method, set the
Output Signal Control bits of the mixer register 44h for
mixer output. To do this, program bits 6:4 of mixer register
44h to 1, 0, and 0, respectively. The volume of the DSP
digital audio playback is controlled by the Audio 1 Play
Volume register (14h).
NOTE: In Telegaming mode, register 14h also controls
the game-compatible first audio channel digital audio
playback. If independent mixer volume control of the
game-compatible and DSP digital audio data is
necessary, use the second method.
Mixing External to the ES1869
The second method is to use the FDXO output pin and mix
the DSP digital audio playback and the game-compatible
digital audio playback in an external audio mixer. To select
this method, set the Output Signal Control bits of mixer
register 44h for mixer output except DAC playback. To do
this, program bits 6:4 of register 44h to 1, 0, and 1,
ISA
Bus
DMA2
FIFO
DMA1
FIFO
Serializer/
16-bit Stereo
CODEC
Mixer
Microphone
Speaker
DAC
ADC
Deserializer
DSP/CODEC
Port
DAC
ADC
DAC
DAC
16-bit Stereo DAC
FDXO
ISA
Bus
DMA2
FIFO
DMA1
FIFO
Serializer/
16-bit Stereo
CODEC
Mixer
Microphone
Speaker
DAC
ADC
Deserializer
DSP/CODEC
Port
DAC
ADC
DAC
DAC
16-bit Stereo DAC
FDXO