Thecasestatement checks if the given expression matches one of the other expressions in the list and branches accordingly. It is typically used to implement a multiplexer. Theif-elseconstruct may not be suitable if there are many conditions to be checked and would synthesize into a priority encod...
When the number of the nesting grows, it becomes difficult to understand the if else statement. The verilog case statement, comes handy in such cases. We will first look at the usage of the case statement and then learn about its syntax and variations. ...
From the previous exercise (always_case2), there would be 256 cases in the case statement. We can reduce this (down to 9 cases) if the case items in the case statement supported don't-care bits. This is what casezis for: It treats bits that have the value z as don't-care in th...
It is also possible for us to use an else-if type statement here but the else statement is more succinct. The behaviour is the same in both cases as the signal can only ever be 0b or 1b in a real circuit. Verilog Case Statement We use the verilog case statement to select a block ...
The plaincasestatement is simple but rigid—everything must be explicitly coded. In some situations, you may want to specify acase itemthat can match multiplecase expressions. This is where “wildcard”case expressionscasezandcasexcome in.casezallows “Z” and “?” to be treated as don’t ...
--assignment_statement_alignment (Format various assignments:{align,flush-left,preserve,infer}); default: infer;--case_items_alignment (Format case items:{align,flush-left,preserve,infer}); default: infer;--class_member_variable_alignment (Format class member variables:{align,flush-left,preserve,...
modulecase_example; 5 reg[2:0]data; 6 7 always@(data)begin 8 case(data) 9 3'h2:$display("value of data is 2"); 10 3'h4:$display("value of data is 4"); 11 3'h5:$display("value of data is 5"); 12 default:$display("default statement is executed for data = %0d",data...
25 Error: VHDL error at shift_reg.vhd(24): can't synthesize logic for statement with conditions that test for the edges of multiple clocks ---同一进程中含有两个或多个if(edge)条件,(一个进程中之能有一个时钟沿) 26 Error: Can't resolve multiple constant drivers for net "datain_reg[22]...
If multiple statements need to be placed inside the if or else part, it needs to be enclosed within begin and end. if ([expression]) Single statement // Use "begin" and "end" blocks for more than 1 statements if ([expression]) begin Multiple statements end // Use else to execute sta...
Verilog之case语句 verilog设计进阶 时间:2014年5月6日星期二 主要收获: 1.学会使用case语句: 2.学会使用随机函数$random. $random: 1.函数说明:$random函数调用时返回一个32位的随机数,它是一个带符号的整形数. 2.产生0~59之间的随机数的样例: reg[23:0]rand; rand={$random}% 60; 3.产生一个在min...