Cirrus-logic CS5376A Manual do Utilizador descarregar pdf (Página 69)

CS5376A

DS612F4 69

Any GPIO pin can be used as an open-drain output

by setting the data value to 0, enabling the pull-up,

and using the GP_DIR direction bits to control the

pin value. This open-drain output configuration

uses the internal pull-up resistor to hold the pin

high when GP_DIR is set as an input, and drives the

pin low when GP_DIR is set as an output.

19.5.1 GPIO Reads in Output Mode

When reading GPIO pins the GP_DATA register

value always reports the current state of the pins, so

a value written in output mode does not necessarily

read back the same value. If a pin in output mode is

written as a logical 1, the CS5376A attempts to

drive the pin high. If an external device forces the

pin low, the read value reflects the pin state and re-

turns a logical 0. Similarly, if an output pin is writ-

ten as a logical 0 but forced high externally, the

read value reflects the pin state and returns a logical

1. In both cases the CS5376A is in contention with

the external device resulting in increased power

consumption.

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Cirrus-logic CS5376A Manual do Utilizador Página 69