HDLBits刷题记录 Circuits—Combinational Logic—Basic Gates

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我是靠谱客的博主默默火车，最近开发中收集的这篇文章主要介绍HDLBits刷题记录 Circuits—Combinational Logic—Basic Gates，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

·Truth tables

解决方法：

1、直接列原始逻辑表达式，走数据流assign

2、将原始逻辑表达式通过化简得到canonical function，再走assign

3、观察Truth table规律，走抽象级(最简算法)

module top_module (
	input x3,
	input x2,
	input x1,
	output f
);
	// This truth table has four minterms. 
	assign f = ( ~x3 & x2 & ~x1 ) | 
				( ~x3 & x2 & x1 ) |
				( x3 & ~x2 & x1 ) |
				( x3 & x2 & x1 ) ;
				
	// It can be simplified, by boolean algebra or Karnaugh maps.
	// assign f = (~x3 & x2) | (x3 & x1);
	
	// You may then notice that this is actually a 2-to-1 mux, selected by x3:
	// assign f = x3 ? x1 : x2;
	
endmodule

·Thermostat 恒温器

module top_module(
	input too_cold, 
	input too_hot,
	input mode,
	input fan_on,
	output heater,
	output aircon,
	output fan
);
	// Reminder: The order in which you write assign statements doesn't matter. 
	// assign statements describe circuits, so you get the same circuit in the end
	// regardless of which portion you describe first.

	// Fan should be on when either heater or aircon is on, and also when requested to do so (fan_on = 1).
	assign fan = heater | aircon | fan_on;
	
	// Heater is on when it's too cold and mode is "heating".
	assign heater = (mode & too_cold);
	
	// Aircon is on when it's too hot and mode is not "heating".
	assign aircon = (~mode & too_hot);
	
	// * Unlike real thermostats, there is no "off" mode here.
	
endmodule

·Even longer vectors 向量元素之间的关系

module top_module( 
    input [99:0] in,
    output [98:0] out_both,
    output [99:1] out_any,
    output [99:0] out_different );
    assign out_both = in[99:1] & in[98:0];
    assign out_any = in[99:1] | in[98:0];
    assign out_different = in ^ {in[0], in[99:1]};

endmodule