Pre Production
WM8941
Figure 41 Example Usage of MODE Pin to Generate a Clock Out in 3-wire Mode
This example shows how the MODE_GPIO register bit interfaces to the MODE pad in the case there
MODE is used as a GPIO output. When MODE_GPIO is set, the internal version of MODE is
overridden to high and the MODE pin output driver is enabled. The pull up, which is used to default
3-wire mode at start-up, is disabled as a power saving measure. MODE_GPIO cannot be set in 2-
wire mode - this would prevent correct operation of the control interface. Internal timing is arranged
to ensure that the override is in place before the pull-up is disabled.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R8
7
MODE_GPIO
0
Selects MODE pin as a GPIO pin
GPIO
0 = MODE is an input. MODE selects 2-
wire mode when low and 3-wire mode
when high.
Control
1 = MODE can be an input or output
under the control of the GPIO control
register. Interface operates in 3-wire
mode regardless of what happens on the
MODE pin.
Table 55 Mode is GPIO Control
Auto-incremental writes are supported in 2 wire and 3 wire modes. This is enabled by default.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R9
1
AUTOINC
1
Auto-Incremental write enable
0=Auto-Incremental writes disabled
Control
Interface
1=Auto-Incremental writes enabled
Table 56 Control Interface
PP, Rev 3.3, December 2007
69
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
