Pre-Production
WM8959
The GPIO input or internal Interrupt event (eg. MICBIAS current detect) is latched as illustrated
below:
Figure 46 GPIO Latch
The de-bounce function on the GPIO input pins enables transient behaviour to be filtered as
illustrated below:
Figure 47 GPIO De-bounce
To implement an edge detect function on a GPIO input, the GPIOn_POL bits may be used to
alternate the GPIO polarity after each edge transition. For example, after a logic 1 has caused an
Interrupt event, the polarity may be inverted prior to resetting the Interrupt register bit. In this way, the
next interrupt event generated by this GPIO will occur when it returns to the logic 0 state. The
GPIOn_POL bit must be reversed after every GPIO edge transition, as illustrated below:
Figure 48 GPIO Edge Detect
PP, May 2008, Rev 3.1
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
