Specifications

74 SAM0025A-062397 ESS Technology, Inc.
ES1879 DATA SHEET
REGISTERS
PRELIMINARY
ES978 Interface Mode Control (67h, R/W)
In the ES1878, the mode of the interface to the ES978
(playback vs record, mono vs full-duplex) was determined
by the state of the CODEC inside the ES1878
automatically. In the ES1879, the mode of the interface is
determined by mixer register 67h.
Bit 2, the ES978 record mixer tracking mode select bit,
determines which mixer (playback or record) in the
ES1879 is tracked (mirrored) by the ES978 record mixer.
It is useful to have the ES978 record mixer track the
ES1879 playback mixer in two situaions. First, if there are
no speakers in the docking station (ES978), the ES978
record mixer is used to collect audio sources from the
docking station and sent to the ES1879 playback mixer.
Second, Spatializer 3-D effects can be added to docking
station audio sources by means of this mode. If bit 2 is set
high, bits 2:0 of mixer register 1Ch must be set to 101.
This register is set to E3h by hardware reset.
Bits Definitions:
Mic Record Volume (68h, R/W)
This registers controls the record volume for the Mic input.
Set low by hardware reset but not by mixer reset.
Audio 2 Record Volume (69h, R/W)
This register controls the record volume for the second
audio channel. Set low by hardware reset but not by mixer
reset.
CD (AuxA) Record Volume (6Ah, R/W)
This register controls the record volume for the CD input.
Set low by hardware reset but not by mixer reset.
Music DAC Record Volume (6Bh, R/W)
This register controls the record volume for the music DAC
(FM or wavetable). Set low by hardware reset but not by
mixer reset.
AuxB Record Volume (6Ch, R/W)
This register controls the record volume for the auxiliary
line input. Set low by hardware reset but not by mixer
reset.
I
2
S Volume (6Dh, R/W)
This register controls the playback volume for the I
2
S input.
Set low by hardware reset but not by mixer reset.
Line Record Volume (6Eh, R/W)
This register controls the record volume for the line input.
Set low by hardware reset but not by mixer reset.
ES978 mix
volume
0
ES978 audio
mix into play-
back enable
ES978 record
mixer tracking
mode select
Interface mode
select
76 5 4 3 2 1 0
Bits Name Description
7:5 ES978
mix vol-
ume
Select mix volume of audio received from
ES978 into playback mixer of the ES1879
when bit 3 of this register is set high.
4 – Reserved. Always write 0.
3 ES978
audio
mix into
playback
enable
1 = Enable audio received from ES978 to mix
into playback mixer of ES1879.
0 = No audio is mixed into the playback mixer
of the ES1879 from the ES978.
2 ES978
record
mixer
tracking
mode
select.
1 = Record mixer in ES978 tracks playback
mixer in ES1879. ES978 playback mixer is
muted except for ES1879 audio.
0 = Record mixer in ES978 tracks record mixer
in ES1879 (default).
1:0 Interface
mode
select
Selects the ES978–ES1879 interface mode.
bit 1
bit 0 mode
0 0 Differential stereo playback to
ES978.
0 1 Differential stereo record from
ES978.
1 0 Mono full-duplex.
1 1 Stereo full-duplex (default).
Mic record volume left Mic record volume right
76543210
Audio 2 record volume left Audio 2 record volume right
76543210
CD record volume left CD record volume right
76543210
Music DAC record volume left Music DAC record volume right
76543210
AuxB record volume left AuxB record volume right
76543210
I
2
S volume left I
2
S volume right
76543210
Line record volume left Line record volume right
76543210