WM8802 datasheet(36/65 Pages) WOLFSON

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WM8802

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PP Rev 1.1 April 2004

GENERAL PURPOSE I/O (GPIO0, GPIO1, GPIO2, GPIO3, GPIOEN)

INITIAL SETTINGS

The modulation function and general-purpose parallel I/O’s share the same pins and therefore cannot

be used simultaneously. INT should be pulled down with a 10k

Ω resistor to use the general-purpose

I/O’s. For the setting method, see page 10.

The general-purpose parallel I/O output function performs parallel conversion of the serial data input

from the micro-controller interface and outputs the resulting data from GPIO0 GPIO1, GPIO2 and

GPIO3. The input function saves the parallel data input to GPIO0, GPIO1, GPIO2, and GPIO3 to

internal registers and reads the contents of these registers with the micro-controller interface.

It is not possible to mix the 4 bit general-purpose I/O’s as inputs and outputs at the same time.

Switching between input and output is done using GPIOEN The general-purpose I/Os all become

input pins when GPIOEN is High and all output pins when GPIOEN is Low.

INPUT/OUTPUT SETTINGS

Data handling for general-purpose I/O is performed using the micro-controller interface and

write/read registers.

General-purpose I/O write settings (Micro-controller

→ Write register → General-purpose I/O output)

Set GPIOEN to Low to output data from general-purpose I/O’s.

Set the data to be output to CCB address 0xE8, command address 0x10 and input registers

DI12 to DI15.

During write operation, make sure "0" is written to modulation function setting registers DI8 to

DI11.

The data written to PI0 to PI3 is output from the general-purpose I/O’s.

General-purpose I/O read settings (General-purpose I/O input

→ Read register → Micro-controller)

Set GPIOEN to High to input data to general-purpose I/O’s.

The input data is saved to CCB address 0xEB and output registers DO0 to DO3.

Data can be sent to the micro-controller by reading GPO0 to GPO3.

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