wm9714l Wolfson Microelectronics plc, wm9714l Datasheet - Page 74

• Manufacturer Part Number: wm9714l
• Description: Ac?97 Audio Codec
• Manufacturer: Wolfson Microelectronics plc

WM9714L
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The properties of the GPIOs are controlled through registers 4Ch to 52h, as shown below.
Table 57 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 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 WM9714L and on the CPU.
4Ch
4Eh
50h
52h
54h
REGISTER
ADDRESS
n
n
n
n
n
BIT
GCn
GPn
GSn
GWn
GIn
LABEL
1
1
0
0
N/A
DEFAULT
GPIO Pin Configuration Control
0 = Output
1 = Input (GC9-15 are always inputs)
GPIO Pin Polarity / Type
Input (GCn = 1)
0 = Active low
1 = Acitve high
GPIO Pin Sticky Control
0 = Not sticky
1 = Sticky
GPIO Pin Wake-up Control
0 = No wake-up (no interrupts generated by
1 = Wake-up (generate interrupts from GPIO)
GPIO Pin Status
Read = Returns status of GPIO
Write = Writing 0 clears sticky bits
GPIO)
DESCRIPTION
PP, Rev 3.2, October 2008
Input (GCn = 1)
0 = Active low
1 = Acitve high
Pre-Production
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