Pre-Production
WM8985
GENERAL PURPOSE INPUT/OUTPUT
The WM8985 has three dual purpose input/output pins.
•
•
•
CSB/GPIO1: CSB / GPIO1 pin
L2/GPIO2: Left channel line input / headphone detection input
R2/GPIO3: Right channel line input / headphone detection input
The GPIO2 and GPIO3 functions are provided for use as jack detection inputs.
The GPIO1 function is provided for use as jack detection input or general purpose output.
The default configuration for the CSB/GPIO1 is to be an input.
When setup as an input, the CSB/GPIO1 pin can either be used as CSB or for jack detection,
depending on how the MODE pin is set.
Table 45 illustrates the functionality of the GPIO1 pin when used as a general purpose output.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R8 (08h)
GPIO
2:0
GPIO1SEL
000
CSB/GPIO1 pin function select:
000 = input (CSB / Jack detection:
depending on MODE setting)
Control
001 = reserved
010 = Temp ok
011 = Amute active
100 = PLL clk output
101 = PLL lock
110 = logic 0
111 = logic 1
3
GPIO1POL
OPCLKDIV
0
GPIO1 Polarity invert
0 = Non inverted
1 = Inverted
5:4
00
PLL Output clock division ratio
00 = divide by 1
01 = divide by 2
10 = divide by 3
11 = divide by 4
6
GPIO1GPD
0
GPIO1 Internal pull-down enable:
0 = Internal pull-down disabled
1 = Internal pull-down enabled
7
8
GPIO1GPU
GPIO1GP
0
0
GPIO1 Internal pull-up enable:
0 = Internal pull-up disabled
1 = Internal pull-up enabled
GPIO1 Open drain enable
0 = Open drain disabled
1 = Open drain enabled
Table 45 CSB/GPIO Control
Note:
If MODE is set to 3 wire mode, CSB/GPIO1 is used as CSB input irrespective of the GPIO1SEL[2:0]
bits.
PP, Rev 3.4, October 2006
83
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
