WM9711 datasheet(42/66 Pages) WOLFSON

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WM9711L

Production Data

PD Rev 4.1 April 2004

The properties of the GPIOs are controlled through registers 4Ch to 52h, as shown below.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

4Ch

GCn

GPIO Pin Configuration

0: Output

1: Input

GC11-15 are always ‘1’

Unused bits GC6-GC10 are always ‘0’

GPIO Pin Polarity / Type

0: Active Low

1: Active High

[GIn = pin level XNOR GPn)

4Eh

GPn

Unused bits GP6-GP10, GP12 and GP13 are

always ‘1’

50h

GSn

GPIO Pin Sticky

1: Sticky

0: Not Sticky

Unused bits GS6-GS10, GS12 and GS13 are

always ‘0’

52h

GWn

GPIO Pin Wake-up

1: Wake Up (generate interrupts from this pin)

0: No wake-up (no interrupts generated)

Unused bits GW6-GW10, GW12 and GW13 are

always ‘0’

54h

GIn

N/A

GPIO Pin Status

Read: Returns status of each GPIO pin

Write: Sets output pin high or low.

(Writing ‘0’ clears sticky bit)

Unused bits GI6-GI10, GI12 and GI13 are

always ‘0’

Table 28 GPIO Control

The following procedure is recommended for handling interrupts:

When the controller receives an interrupt, check register 54h. For each GPIO bit in descending order

of priority, check if the bit is ‘1’. If yes, execute corresponding interrupt routine, then write ‘0’ to

corresponding bit in 54h. If no, continue to next lower priority GPIO. After all GPIOs have been

checked, check if interrupt still present or no. If yes, repeat procedure. If no, then jump back to

process that ran before the interrupt.

If the system CPU cannot execute such an interrupt routine, it may be preferable to switch internal

signals (such as PENDOWN) directly onto the GPIO pins. However, in this case the interrupt signals

cannot be made sticky, and more GPIO pins are tied up both on the WM9711L and on the CPU.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

GE2

GPIO2 / IRQ output select

0: Pin 45 disconnected from GPIO logic

set 4Ch, bit 2 to ‘0’ to output IRQ signal

1: Pin 45 connected to GPIO logic (IRQ disabled)

56h

GPIO pins

function

select

GE5

GPIO5 / SPDIF output select

0: Pin 48 = SPDIF (disconnected from GPIO logic)

set 4Ch, bit 5 to ‘0’ to output SPDIF signal

1: Pin 48 connected to GPIO logic (SPDIF

disabled)

Table 29 Using GPIO Pins for Non-GPIO Functions

WM9711 Datasheet(PDF) 42 Page - Wolfson Microelectronics plc

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