WM8978_06 Wolfson Microelectronics Ltd., WM8978_06 Datasheet - Page 85

• Manufacturer Part Number: WM8978_06
• Description: Stereo Codec With Speaker Driver
• Manufacturer: Wolfson Microelectronics Ltd.

Pre-Production
GENERAL PURPOSE INPUT/OUTPUT
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Figure 44 u-Law Companding
Figure 45 A-Law Companding
The WM8978 has three dual purpose input/output pins.
The GPIO2 and GPIO3 functions are provided for use as jack detection inputs.
The GPIO1 function is provided for use as a jack detection input or a general purpose output.
The default configuration for the CSB/GPIO1 pin 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 49 illustrates the functionality of the GPIO1 pin when used as a general purpose output.
120
100
120
100
80
60
40
20
80
60
40
20
0
0
CSB/GPIO1: CSB / GPIO pin
L2/GPIO2: Left channel line input / headphone detection input
R2/GPIO3: Right channel line input / headphone detection input
0
0
0.1
0.2
0.2
0.3
u-law Companding
A-law Companding
0.4
Normalised Input
0.4
Normalised Input
0.5
0.6
0.6
0.7
0.8
0.8
0.9
PP Rev 3.0 May 2006
1
1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
WM8978
85