STM8S datasheet(105/467 Pages) STMICROELECTRONICS

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General purpose I/O ports (GPIO)

113

General purpose I/O ports (GPIO)

11.1

Introduction

General purpose input/output ports are used for data transfers between the chip and the

external world. An I/O port can contain up to eight pins. Each pin can be individually

programmed as a digital input or digital output. In addition, some ports may have alternate

functions like analog inputs, external interrupts, input/output for on-chip peripherals. Only

one alternate function can be mapped to a pin at a time, the alternate function mapping is

controlled by option byte. Refer to the datasheet for a description of the option bytes.

An output data register, input data register, data direction register and two configuration

registers are associated with each port. A particular port will behave as an input or output

depending on the status of the data direction register of the port.

11.2

GPIO main features

•

Port bits can be configured individually

•

Selectable input modes: floating input or input with pull-up

•

Selectable output modes: push-pull output or pseudo-open-drain.

•

Separate registers for data input and output

•

External interrupts can be enabled and disabled individually

•

Output slope control for reduced EMC noise

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Alternate function I/Os for on-chip peripherals

•

Input Schmitt trigger can be disabled on analog inputs for reduced power consumption

•

Read-modify-write possible on data output latch

•

5 V-tolerant inputs

•

I/O state guaranteed in voltage range 1.6 V to VDDIOmax

STM8S Datasheet(PDF) 105 Page - STMicroelectronics