资料介绍
Implementing Keypad Scanners with CoolRunner-II
This application note provides a functional description of Verilog source code for a keypad
scanner. The code is used to target the lowest density, 32-macrocell CoolRunnerTM-II
XC2C32A CPLD device in a CP56 package (6 mm x 6 mm). The keypad accommodated in this
design has 8 rows and 8 columns. The design can easily be scaled to target keypads with more
or less rows/columns. For instance, a keypad with 7 rows and 7 columns would allow the
design to fit in the smallest QFG32 package (5 mm x 5 mm). To obtain the Verilog source code
described in this document, see “Verilog Code,” page 4, for instructions.
As handheld devices such as cell phones pack more and more features into them, they require
more effective ways of entering data. Most cell phones, for example, use the standard DTMF
style keypad and a multi-tap process to enter alphanumeric data; however, for larger amounts
of data multi-tapping becomes cumbersome. More and more high-end phones are therefore
employing QWERTY keypads that make entering data easier and quicker.
Going from a DTMF to a QWERTY keypad requires more I/O. For instance, a DTMF keypad
might have 4 rows and 3 columns, where a QWERTY keypad might have 8 rows and 8
columns. This can vary depending on the requirements.
Typically, a processor (or ASIC) is used to interface to the keypad’s rows and columns. The
processor scans the rows and monitors the columns for a logic change. When a change
occurs, it indicates that one of the buttons in that column was pressed. By knowing which row
was being scanned, and which column changed state, the processor can deduce which
specific button was pushed. Additional functions such as debounce are also typically
employed. Figure 1 shows how a simple 4 x 4 keypad uses 8 GPIO of a processor.
- AI遇冷?2023从融资再看AI“芯”赛道? 0次下载
- 2023可穿戴设备行业技术与市场分析 10次下载
- 2023年IPO上市“芯”动态 1次下载
- 2023国产SiC上车关键年 4次下载
- 国际形势突变,中国芯片公司 能否“风景这边独好” 1次下载
- 用Arduino KeyPad猜数字 0次下载
- RC ONE Keypad MX(USB适配器)开源 2次下载
- 高效高功率同步整流升压DC-DC芯片AMT6802 19次下载
- 华为统一通信与协作市场发展趋势白皮书下载 1次下载
- Keypad 0次下载
- Implementing the Teridian 73S8 27次下载
- TCA8418E,pdf(Controlled Keypad 20次下载
- TCA8418,pdf(Controlled Keypad 49次下载
- Multipurpose Scanners for Agil 5次下载
- Implementing Double Data Rate 24次下载
- 关于AI遗传算法的详解 8.3w次阅读
- 宽禁带器件和仿真环境介绍 1317次阅读
- 微雪电子电容触摸 按键模块简介 1848次阅读
- 微雪电子AD按键模块简介 1503次阅读
- 微雪电子4x4矩阵式按键模块小键盘简介 2450次阅读
- 微雪电子5 IO 按键模块 小键盘介绍 1025次阅读
- dfrobot1602 LCD显示器扩展板 V2.0简介 1708次阅读
- dfrobotLED Keypad Shield 数码管扩展板简介 1374次阅读
- 在贴片加工厂中有哪些安全防护需要了解 1197次阅读
- 复合放大器实现高精度的高输出驱动能力 获得最佳的性能 1468次阅读
- dfrobot LCD Keypad Shield 按键扩展板介绍 2078次阅读
- 用降压型稳压器或线性稳压器电源时值来会为负载供电 872次阅读
- 锂电池并联充电时保护板均衡原理 2.7w次阅读
- 51单片机的电子测速里程防盗报警器设计 775次阅读
- 更小更智能的电机控制器推进HEV/EV市场 1023次阅读
下载排行
本周
- 1电子电路原理第七版PDF电子教材免费下载
- 0.00 MB | 1491次下载 | 免费
- 2单片机典型实例介绍
- 18.19 MB | 95次下载 | 1 积分
- 3S7-200PLC编程实例详细资料
- 1.17 MB | 27次下载 | 1 积分
- 4笔记本电脑主板的元件识别和讲解说明
- 4.28 MB | 18次下载 | 4 积分
- 5开关电源原理及各功能电路详解
- 0.38 MB | 11次下载 | 免费
- 6100W短波放大电路图
- 0.05 MB | 4次下载 | 3 积分
- 7基于单片机和 SG3525的程控开关电源设计
- 0.23 MB | 4次下载 | 免费
- 8基于AT89C2051/4051单片机编程器的实验
- 0.11 MB | 4次下载 | 免费
本月
- 1OrCAD10.5下载OrCAD10.5中文版软件
- 0.00 MB | 234313次下载 | 免费
- 2PADS 9.0 2009最新版 -下载
- 0.00 MB | 66304次下载 | 免费
- 3protel99下载protel99软件下载(中文版)
- 0.00 MB | 51209次下载 | 免费
- 4LabView 8.0 专业版下载 (3CD完整版)
- 0.00 MB | 51043次下载 | 免费
- 5555集成电路应用800例(新编版)
- 0.00 MB | 33562次下载 | 免费
- 6接口电路图大全
- 未知 | 30320次下载 | 免费
- 7Multisim 10下载Multisim 10 中文版
- 0.00 MB | 28588次下载 | 免费
- 8开关电源设计实例指南
- 未知 | 21539次下载 | 免费
总榜
- 1matlab软件下载入口
- 未知 | 935053次下载 | 免费
- 2protel99se软件下载(可英文版转中文版)
- 78.1 MB | 537793次下载 | 免费
- 3MATLAB 7.1 下载 (含软件介绍)
- 未知 | 420026次下载 | 免费
- 4OrCAD10.5下载OrCAD10.5中文版软件
- 0.00 MB | 234313次下载 | 免费
- 5Altium DXP2002下载入口
- 未知 | 233046次下载 | 免费
- 6电路仿真软件multisim 10.0免费下载
- 340992 | 191183次下载 | 免费
- 7十天学会AVR单片机与C语言视频教程 下载
- 158M | 183277次下载 | 免费
- 8proe5.0野火版下载(中文版免费下载)
- 未知 | 138039次下载 | 免费
评论
查看更多