WM8904
Pre-Production
EQ GAIN SETTING
GAIN (DB)
00000
-12
-11
-10
-9
00001
00010
00011
00100
-8
00101
-7
00110
-6
00111
-5
01000
-4
01001
-3
01010
-2
01011
-1
01100
0
01101
+1
01110
+2
01111
+3
10000
+4
10001
+5
10010
+6
10011
+7
10100
+8
10101
10110
+9
+10
+11
+12
Reserved
10111
11000
11001 to 11111
Table 26 EQ Gain Control
RETUNETM MOBILE MODE
ReTuneTM Mobile mode provides a comprehensive facility for the user to define the cut-off/centre
frequencies and filter bandwidth for each EQ band, in addition to the gain controls already described.
This enables the EQ to be accurately customised for a specific transducer characteristic or desired
sound profile.
The EQ enable and EQ gain controls are the same as defined for the default mode. The additional
coefficients used in ReTuneTM Mobile mode are held in registers R140 to R157. These coefficients
are derived using tools provided in Wolfson’s WISCE™ evaluation board control software.
Please contact your local Wolfson representative for more details.
EQ FILTER CHARACTERISTICS
The filter characteristics for each frequency band are shown in Figure 30 to Figure 34. These figures
show the frequency response for all available gain settings, using default cut-off/centre frequencies
and bandwidth.
PP, Rev 3.3, September 2012
60
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
