1. 首页
  2. 文章中心
  3. 读书笔记

【计算机系统要素】使用D触发器实现寄存器、内存和计数器D触发器寄存器内存计数器

210 阅读 0 评论
我是靠谱客的博主 鲜艳蚂蚁，这篇文章主要介绍【计算机系统要素】使用D触发器实现寄存器、内存和计数器D触发器寄存器内存计数器，现在分享给大家，希望可以做个参考。

本文是笔者拜读《计算机系统要素》第3章（时序逻辑）的实践项目。
本文的HDL程序所调用的组合逻辑模块来自前几篇博客。

目录

  • D触发器
  • 寄存器
    • 1比特位寄存器
    • 多比特位寄存器
  • 内存
    • 8字内存
    • 64字内存
    • 512字内存
    • 4K字内存
    • 16K字内存
  • 计数器

D触发器

在这里插入图片描述
在这里插入图片描述
DFF的输出被赋予了上个时钟周期的输入，所有的DFF门都连接同一个主时钟，所有时序芯片都在主时钟频率的协调下共同工作。

和Nand门一样，DFF门在计算机体系中处于非常底层的位置，计算机中的所有时序芯片（寄存器、内存、计数器）都基于大量的DFF门。

DFF的物理实现是个复杂的任务，它使用反馈电路（仅基于Nand门）连接几个基本的逻辑门。

寄存器

1比特位寄存器

在这里插入图片描述
如果希望寄存器开始存储一个新值，可以把这个值置于in输入口，然后将load位设为1；如果希望寄存器一直存储它的内部值直到新的指令到来，就将load设置为0。
在这里插入图片描述
在这里插入图片描述

CHIP Bit {
    IN in, load; // t
    OUT out; // t+1

    PARTS:
    // Put your code here:
    Mux(a = o1, b = in, sel = load, out = o2);
    DFF(in = o2, out = out);
    DFF(in = o2, out = o1);
}

内部接线o1的默认初值是false，即低电平。
输入是t时刻的，输出是t+1时刻的，该输出又是t+2时刻输出的一部分。

多比特位寄存器

在这里插入图片描述
在这里插入图片描述
在这里插入图片描述
读：要读取寄存器的内容，只需获取它的输出。
写：要将新数据d写入寄存器，只需将d置于in输入管脚，并将load输入管脚的值设为1，这样，在下一个时钟周期，寄存器被赋予新的数据值，输出变成了d。

CHIP Register {
    IN in[16], load;
    OUT out[16];

    PARTS:
    // Put your code here:
    Bit(in = in[0], load = load, out = out[0]);
    Bit(in = in[1], load = load, out = out[1]);
    Bit(in = in[2], load = load, out = out[2]);
    Bit(in = in[3], load = load, out = out[3]);
    Bit(in = in[4], load = load, out = out[4]);
    Bit(in = in[5], load = load, out = out[5]);
    Bit(in = in[6], load = load, out = out[6]);
    Bit(in = in[7], load = load, out = out[7]);
    Bit(in = in[8], load = load, out = out[8]);
    Bit(in = in[9], load = load, out = out[9]);
    Bit(in = in[10], load = load, out = out[10]);
    Bit(in = in[11], load = load, out = out[11]);
    Bit(in = in[12], load = load, out = out[12]);
    Bit(in = in[13], load = load, out = out[13]);
    Bit(in = in[14], load = load, out = out[14]);
    Bit(in = in[15], load = load, out = out[15]);
}

一个寄存器的大小就是一个字的宽度。

内存

在这里插入图片描述
随机访问存储器（RAM），是由n（表示内存尺寸）个w（表示内存宽度）位寄存器组成的阵列。
在这里插入图片描述
在这里插入图片描述

k是地址总线的个数。

读：要读取编号为m的寄存器，我们先将m置于address输入管脚。RAM的直接存取逻辑将选中编号为m的寄存器，于是该寄存器将它的输出发送到RAM的输出管脚，这是个不涉及时间的组合逻辑操作。

写：要将新的数据值d写入编号为m的寄存器，我们同样将m置于address输入管脚，并将d置于in管脚，然后确认load为1。这样使得RAM的直接存取逻辑去选中m号寄存器，load位来使能写操作，在下一个时钟周期里，被选中的寄存器将会被赋予新的数据值d，RAM的输出值也变成了d。

8字内存

CHIP RAM8 {
    IN in[16], load, address[3];
    OUT out[16];

    PARTS:
    // Put your code here:
    DMux8Way(in = true, sel = address, a = ram0, b = ram1, c = ram2, d = ram3, e = ram4, f = ram5, g = ram6, h = ram7);
    // 寻址，写/读数据
    // 每个寄存器要么将数据置为in，要么维持原值不变
    And(a = ram0, b = load, out = s0);
    Register(in = in, load = s0, out = o0);
    And(a = ram1, b = load, out = s1);
    Register(in = in, load = s1, out = o1);
    And(a = ram2, b = load, out = s2);
    Register(in = in, load = s2, out = o2);
    And(a = ram3, b = load, out = s3);
    Register(in = in, load = s3, out = o3);
    And(a = ram4, b = load, out = s4);
    Register(in = in, load = s4, out = o4);
    And(a = ram5, b = load, out = s5);
    Register(in = in, load = s5, out = o5);
    And(a = ram6, b = load, out = s6);
    Register(in = in, load = s6, out = o6);
    And(a = ram7, b = load, out = s7);
    Register(in = in, load = s7, out = o7);
    // 通过八选一选择器，输出数据
    Mux8Way16(a = o0, b = o1, c = o2, d = o3, e = o4, f = o5, g = o6, h = o7, sel = address, out = out);
}

仅当某个寄存器被选中且load为1，才改变该寄存器的值。
在时序逻辑中，需要经过一定的时钟周期数才能使输入流到输出；而在组合逻辑中，输入一瞬间就能流到输出。

64字内存

CHIP RAM64 {
    IN in[16], load, address[6];
    OUT out[16];

    PARTS:
    // Put your code here:
    DMux8Way(in = true, sel = address[3..5], a = ram0, b = ram1, c = ram2, d = ram3, e = ram4, f = ram5, g = ram6, h = ram7);
    And(a = ram0, b = load, out = s0);
    RAM8(in = in, load = s0, address = address[0..2], out = o0);
    And(a = ram1, b = load, out = s1);
    RAM8(in = in, load = s1, address = address[0..2], out = o1);
    And(a = ram2, b = load, out = s2);
    RAM8(in = in, load = s2, address = address[0..2], out = o2);
    And(a = ram3, b = load, out = s3);
    RAM8(in = in, load = s3, address = address[0..2], out = o3);
    And(a = ram4, b = load, out = s4);
    RAM8(in = in, load = s4, address = address[0..2], out = o4);
    And(a = ram5, b = load, out = s5);
    RAM8(in = in, load = s5, address = address[0..2], out = o5);
    And(a = ram6, b = load, out = s6);
    RAM8(in = in, load = s6, address = address[0..2], out = o6);
    And(a = ram7, b = load, out = s7);
    RAM8(in = in, load = s7, address = address[0..2], out = o7);

    Mux8Way16(a = o0, b = o1, c = o2, d = o3, e = o4, f = o5, g = o6, h = o7, sel = address[3..5], out = out);
}

高3位寻址芯片，低3位在芯片里寻址字。

512字内存

CHIP RAM512 {
    IN in[16], load, address[9];
    OUT out[16];

    PARTS:
    // Put your code here:
    DMux8Way(in = true, sel = address[6..8], a = ram0, b = ram1, c = ram2, d = ram3, e = ram4, f = ram5, g = ram6, h = ram7);
    And(a = ram0, b = load, out = s0);
    RAM64(in = in, load = s0, address = address[0..5], out = o0);
    And(a = ram1, b = load, out = s1);
    RAM64(in = in, load = s1, address = address[0..5], out = o1);
    And(a = ram2, b = load, out = s2);
    RAM64(in = in, load = s2, address = address[0..5], out = o2);
    And(a = ram3, b = load, out = s3);
    RAM64(in = in, load = s3, address = address[0..5], out = o3);
    And(a = ram4, b = load, out = s4);
    RAM64(in = in, load = s4, address = address[0..5], out = o4);
    And(a = ram5, b = load, out = s5);
    RAM64(in = in, load = s5, address = address[0..5], out = o5);
    And(a = ram6, b = load, out = s6);
    RAM64(in = in, load = s6, address = address[0..5], out = o6);
    And(a = ram7, b = load, out = s7);
    RAM64(in = in, load = s7, address = address[0..5], out = o7);

    Mux8Way16(a = o0, b = o1, c = o2, d = o3, e = o4, f = o5, g = o6, h = o7, sel = address[6..8], out = out);
}

4K字内存

CHIP RAM4K {
    IN in[16], load, address[12];
    OUT out[16];

    PARTS:
    // Put your code here:
    DMux8Way(in = true, sel = address[9..11], a = ram0, b = ram1, c = ram2, d = ram3, e = ram4, f = ram5, g = ram6, h = ram7);
    And(a = ram0, b = load, out = s0);
    RAM512(in = in, load = s0, address = address[0..8], out = o0);
    And(a = ram1, b = load, out = s1);
    RAM512(in = in, load = s1, address = address[0..8], out = o1);
    And(a = ram2, b = load, out = s2);
    RAM512(in = in, load = s2, address = address[0..8], out = o2);
    And(a = ram3, b = load, out = s3);
    RAM512(in = in, load = s3, address = address[0..8], out = o3);
    And(a = ram4, b = load, out = s4);
    RAM512(in = in, load = s4, address = address[0..8], out = o4);
    And(a = ram5, b = load, out = s5);
    RAM512(in = in, load = s5, address = address[0..8], out = o5);
    And(a = ram6, b = load, out = s6);
    RAM512(in = in, load = s6, address = address[0..8], out = o6);
    And(a = ram7, b = load, out = s7);
    RAM512(in = in, load = s7, address = address[0..8], out = o7);

    Mux8Way16(a = o0, b = o1, c = o2, d = o3, e = o4, f = o5, g = o6, h = o7, sel = address[9..11], out = out);
}

16K字内存

CHIP RAM16K {
    IN in[16], load, address[14];
    OUT out[16];

    PARTS:
    // Put your code here:
    DMux4Way(in = true, sel = address[12..13], a = ram0, b = ram1, c = ram2, d = ram3);
    
    And(a = ram0, b = load, out = s0);
    RAM4K(in = in, load = s0, address = address[0..11], out = o0);
    And(a = ram1, b = load, out = s1);
    RAM4K(in = in, load = s1, address = address[0..11], out = o1);
    And(a = ram2, b = load, out = s2);
    RAM4K(in = in, load = s2, address = address[0..11], out = o2);
    And(a = ram3, b = load, out = s3);
    RAM4K(in = in, load = s3, address = address[0..11], out = o3);

    Mux4Way16(a = o0, b = o1, c = o2, d = o3, sel = address[12..13], out = out);
}

计数器

指令地址计数器：内容是计算机下一时钟周期要读取和执行的指令地址。大多数情况下，计数器在每个时钟周期内做简单的加1操作，其它情况下要进行跳转，甚至置0（重新执行程序）。

我们需要一个可重载、可重置的计数器。

当inc=1时，计数器在每个时钟周期自加，输出值out(t)=out(t-1)+1；如果想要将计数器重置为0，就将reset置为1；如果想要将其初始化为某个计数值d，就将d置于in输入管脚然后将load位置1。
在这里插入图片描述
在这里插入图片描述

CHIP PC {
    IN in[16],load,inc,reset;
    OUT out[16];

    PARTS:
    // Put your code here:
    Xor16(a = in, b = in, out = reseto); //reset输出
    Inc16(in = ot, out = inco); // inc输出
    
    Mux16(a = in, b = reseto, sel = reset, out = o1);
    Or(a = reset, b = load, out = or1);
    Mux16(a = inco, b = o1, sel = or1, out = o2);

    Or(a = or1, b = inc, out = or2);
    Register(in = o2, load = or2, out = out);
    Register(in = o2, load = or2, out = ot);
}

注意load、inc和reset的优先级不一样。

最后

以上就是鲜艳蚂蚁最近收集整理的关于【计算机系统要素】使用D触发器实现寄存器、内存和计数器D触发器寄存器内存计数器的全部内容，更多相关【计算机系统要素】使用D触发器实现寄存器、内存和计数器D触发器寄存器内存计数器内容请搜索靠谱客的其他文章。

本图文内容来源于网友提供，作为学习参考使用，或来自网络收集整理，版权属于原作者所有。
点赞(139)

相关文章

格雷码计数器实现
格雷码计数器实现
异步八进制减法计数器
异步八进制减法计数器
碎碎念：路由原理逻辑图路由原理逻辑
碎碎念：路由原理逻辑图路由原理逻辑
同步八进制加法计数器
同步八进制加法计数器
【计算机系统要素】使用D触发器实现寄存器、内存和计数器D触发器寄存器内存计数器
【计算机系统要素】使用D触发器实现寄存器、内存和计数器D触发器寄存器内存计数器
数电实验：用74LS160/74LS161设计6进制，96进制，140进制计数器
数电实验：用74LS160/74LS161设计6进制，96进制，140进制计数器
数电课设交通灯控制器
数电课设交通灯控制器
数字集成电路及其版图设计：带有预置数功能的8位二进制加减计数器设计及版图实现数字集成电路及其版图设计带有预置数功能的8位二进制加减计数器设计及版图实现
数字集成电路及其版图设计：带有预置数功能的8位二进制加减计数器设计及版图实现数字集成电路及其版图设计带有预置数功能的8位二进制加减计数器设计及版图实现

评论列表共有 0 条评论

立即
投稿
返回
顶部