MCP23X08EV【PDF 1/10 页】BOARD EVALUATION FOR MCP23X08

收藏本站

您好，
买卖IC网欢迎您。
请登录
免费注册

买卖IC网

Sheet目录1229

[1页]2页 3页 4页 5页

AN1043

Unique Features of the MCP23X08/17 GPIO Expanders

Author:

Pat Richards

Microchip Technology Inc.

I/O PORT DESCRIPTION

The I/O port is highly configurable for maximum

flexibility. Figure 1 is a simplified block diagram of an

INTRODUCTION

GPIO expanders provide easy I/O expansion using

standard serial interfaces. GPIO products are used to

increase the I/O on an MCU or provide remote I/O

using a serial interface.

This application note discusses the feature set and use

of the MCP23X08/17 (8-bit and 16-bit) GPIO Expand-

ers.

The MCP23X08 are 8-bit GPIO Expanders:

? MCP23008: I 2 C? Interface

? MCP23S08: SPI Interface

The MCP23X17 are 16-bit GPIO Expanders:

? MCP23017: I 2 C Interface

? MCP23S17: SPI Interface

The functions and features of the MCP23X08 and

MCP23X17 are basically the same, except where

otherwise noted.

FEATURES

This application note discusses some of the features of

the MCP23X08/17 and how they may be used in an

application:

? I/O Port Description

? 8/16-Bit Mode (MCP23X17 only)

? Interrupt Features

- Mapping Interrupts

- Mirroring Interrupts (MCP23X17 only)

- Servicing Interrupts

? Internal Address Pointer Control

? Hardware Address Pin on SPI

? 2006 Microchip Technology Inc.

I/O port pin. The port can either drive logic levels on the

pin, or read logic levels from the pad. The level on the

pad can be read at any time, regardless if the pin is

configured as an input or an output.

The IODIR register controls the direction of the pins

(input or output). More specifically, the IODIR registers

simply enables/disables the output driver. When the

driver is activated (IODIR = 0), the pad is driven to the

state in the latch register (OLAT). When deactivated

(IODIR = 1), the driver is high impedance.

The I/O port has multiple, individual configurations.

Each pin can …

? … be configured as an input. The output driver is

disabled (high impedance)

? … be configured as an output. The output driver

is enabled and the value in the latch is driven on

the pin.

? … enable a weak pull-up resistor

? … emulate an open-drain configuration. This is

accomplished by clearing the output latch (OLAT)

bit to a zero and using the direction register

(IODIR) to set the level on the pin. A pull-up

resistor is required to pull the pin to voltage when

the pin is an input

- To drive a 0: configure the pin as an output

(IODIR = 0) so the port drives whatever is in

OLAT (logic 0 in this case)

- To float a 1: set the pin as an input

(IODIR = 1). The output driver is disabled

and the pull-up resistor pulls the pin to a

logic 1

DS01043A-page 1

发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

*型号	*数量	厂商	批号	封装

添加更多采购

采购需求

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

我的联系方式