如何对AT91微控制器外接 4x4 键盘

下载资料简介：
官方技术手册，自己可以在网上找到。
Introduction
This Application Note describes programming techniques implemented on the AT91
ARM-based microcontroller for scanning a 4x4 Keyboard matrix usually found in both
consumer and industrial applications for numeric data entry.
AT91 Keyboard interface
In this application, a 4x4 matrix keypad requiring eight Input/Output ports for interfacing
is used as an example.
Rows are connected to Peripheral Input/Output (PIO) pins configured as output. Columns
are connected to PIO pins configured as input with interrupts. In this
configuration, four pull-up resistors must be added in order to apply a high level on the
corresponding input pins as shown in Figure 1. The corresponding hexadecimal value
of the pressed key is sent on four LEDs.

备注：：
本站收集200多G的绝对实用的电子资料,但是站长还是个身无分文的学生,没有钱购买服务器,大量的资料没有办法供大家下载。但是，站长对这些资料进行了细致的分类，给大家一个资料索引,让大家更好的收集相关领域资料。本站资料部分来自互联网，朋友们可以在互联网上搜索到这些资料。当站长把资料整理完毕(大概需要1个月)后，会想办法让这些资料跟大家见面，也许用BT供大家下载,请大家耐心等待！