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目 录
引 言..............................................................................................................................................7
1.概 述..........................................................................................................................................8
1.1 等精度频计的简介和意义 ...........................................................................................8
1.2 FPGA 的简介...................................................................................................................8
1.2.1 可编程逻辑器件 FPGA 的基本结构.....................................................................................8
1.2.2 FPGA 的设计方法与要求 .................................................................................................9
1.2.4FPGA 设计工具.....................................................................................................................10
2 .等精度频计的原理分析 ...........................................................................................................11
2.1 等精度频计的原理 .........................................................................................................11
3. 硬件电路设计............................................................................................................................13
3.1 总体方案设计 ..................................................................................................................13
3.2 测频模块的工作原理及设计 ..........................................................................................14
3.2.1 FPGA 测频专用模块逻辑设计............................................................................................14
3.2.3 控制部件设计.....................................................................................................................16
3.2.4 计数部件设计.....................................................................................................................16
3.2.5 脉冲宽度测量和占空比测量模块设计.............................................................................16
3.3 单片机主控模块 ..............................................................................................................17
3.3.1 AT89C51 单片机性能.........................................................................................................17
3.3.2 单片机控制电路.................................................................................................................19
3.4 外围电路设计 ..................................................................................................................20
3.4.1 键盘接口电路.....................................................................................................................20
3.4.2 显示电路.............................................................................................................................20
4.软件设计......................................................................................................................................22
4.1 本系统 FPGA 模块的顶层设计 ........................................................................................22
4.2 FPGA 模块仿真 ................................................................................................................22
4.3 单片机的汇编语言编程 ..................................................................................................23
4.3.1 单片机主程序.....................................................................................................................23
4.3.3 键盘扫描、时间值输入及计数值计算子程序.................................................................24
5.附录..............................................................................................................................................25
6.附图..............................................................................................................................................45
7.结束语..........................................................................................................................................46
8.致 谢..........................................................................................................................................47
参考文献..........................................................................................................................................48