Production Data
WM8955BL
LOUT2/ROUT2 OUTPUTS
The LOUT2 and ROUT2 output pins are essentially similar to LOUT1 and ROUT1, but they are
independently controlled and can drive an 32Ω BTL earpiece. For BTL drive, the ROUT2 signal must
be inverted (ROUT2INV = 1), so that the left and right channel are mixed to mono in the earpiece [L-(-
R) = L+R].
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
similar to LOUT1VOL
R40 (28h)
LOUT2
6:0
LOUT2VOL
1111001
(0dB)
0
Volume
7
LO2ZC
Left zero cross enable
1 = Change gain on zero cross only
0 = Change gain immediately
similar to LO1VU
8
LO2VU
0
R41 (29h)
ROUT2
6:0
ROUT2VOL
1111001
(0dB)
0
similar to ROUT1VOL
Volume
7
RO2ZC
Right zero cross enable
1 = Change gain on zero cross only
0 = Change gain immediately
similar to RO1VU
8
RO2VU
TOEN
0
1
0
R23 (17h)
0
as for LOUT1 / ROUT1
R24 (18h)
4
ROUT2INV
ROUT2 Invert
Additional (2)
0 = No Inversion (0° phase shift)
1 = Signal inverted (180° phase shift)
Table 15 LOUT2/ROUT2 Control
MONO OUTPUT
The MONOOUT pin can drive a mono line output. The signal volume on MONOOUT can be adjusted
under software control by writing to MONOOUTVOL.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R42 (2Ah)
MONOOUT
Volume
6:0
MONOOUT
VOL
1111001
(0dB)
MONOOUT Volume
1111111 = +6dB
… (80 steps)
0110000 = -67dB
0101111 to 0000000 = Analogue MUTE
MONOOUT zero cross enable
1 = Change gain on zero cross only
0 = Change gain immediately
as for LOUT1 / ROUT1
7
MOZC
TOEN
0
1
R23 (17h)
0
Table 16 MONOOUT Volume Control
OUT3 OUTPUT
The OUT3 pin can drive a 16Ω or 32Ω headphone or a line output or be used as a DC reference for a
headphone output. It can be selected to either drive out an inverted ROUT1 or inverted MONOOUT
for e.g. an earpiece drive between OUT3 and LOUT1 or differential output between OUT3 and
MONOOUT.
OUT3SW selects the mode of operation required.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
00
DESCRIPTION
R24 (18h)
8:7
OUT3SW
OUT3 select
00 : VREF
Additional (2)
01 : ROUT1
10 : MONOOUT
11 : right mixer output
Table 17 OUT3 Select
PD Rev 4.1 February 2007
25
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
