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WM8581
w
PP Rev 1.0 March 2006
51
OSC
CLK
(MHz)
PRE-
SCALE
_x
F
1
(MHz)
F
2
(MHz)
R PLLx_N
(Hex)
PLLx_K
(Hex)
FREQ
MODE_x
[1:0]
POST-
SCALE_x
PLLxCLK
(MHz)
12 0 12
98.304
8.192
8 C49BA 00
1 24.576
12 0 12
98.304
8.192
8 C49BA 01
0 24.576
12 0 12
98.304
8.192
8 C49BA 01
1 12.288
12 0 12
98.304
8.192
8 C49BA 10
0 12.288
12 0 12
98.304
8.192
8 C49BA 10
1 6.144
12 0 12
98.304
8.192
8 C49BA 11
0 8.192
12 0 12
98.304
8.192
8 C49BA 11
1 4.096
24 1 12
90.3168
7.5264
7
21B089 00
1 22.5792
24 1 12
90.3168
7.5264
7
21B089 01
0 22.5792
24 1 12
90.3168
7.5264
7
21B089 01
1 11.2896
24 1 12
90.3168
7.5264
7
21B089 10
0 11.2896
24 1 12
90.3168
7.5264
7
21B089 10
1 5.6448
24 1 12
90.3168
7.5264
7
21B089 11
0 7.5264
24 1 12
90.3168
7.5264
7
21B089 11
1 3.7632
27 1 13.5
98.304
7.2818
7
1208A5 00
1 24.576
27 1 13.5
98.304
7.2818
7
1208A5 01
1 12.288
27 1 13.5
90.3168
6.6901
6
2C2B24 00
1 22.5792
27 1 13.5
90.3168
6.6901 6 2C2B24 01 1
11.2896
Table 44 User Mode PLL Configuration Examples
When considering settings not shown in this table, the key configuration parameters which must be selected
for optimum operation are:
•
90MHz
f
2
100MHz
•
5
PLLx_N
13
•
OSCCLOCK = 10 to 14.4MHz or 16.28 to 27MHz
CLOCK OUTPUT (CLKOUT) AND MCLK OUTPUT (MCLK)
The clock output (CLKOUT) pin can be used as a clock output. This pin is intended to be used as a clock
source pin for providing the central clock reference for an audio system.
The CLKOUT clock source can be selected from OSCCLK, PLLACLK or PLLBCLK. The control bits
for the CLKOUT signal are shown in Table 45.
The MCLK pin can be configured as an input or output – the WM8581 should be powered down when
switching MCLK between an input and an output. As an output, MCLK can be sourced from
OSCCLK, PLLACLK or PLLBCLK.
REGISTER
ADDRESS
BIT LABEL DEFAULT
DESCRIPTION
6:5
MCLKOUTSRC
00
MCLK pin output source
00 = Input – Source MCLK pin
01 = Output – Source PLLACLK
10 = Output – Source PLLBCLK
11 = Output – Source OSCCLK
R7
PLLB 4
07h
8:7
CLKOUTSRC
11
CLKOUT pin source
00 = No Output (tristate)
01 = Output – Source PLLACLK
10 = Output – Source PLLBCLK
11 = Output – Source OSCCLK
Table 45 MCLK and CLKOUT Control