4 5 (#5) a <= b;// non-blocking assignment with LHS···3 6 7 a <= (#5) b;// non-blocking assignment with RHS···4 8 9 assign (#5) a = b;// continuous assignment with LHS···5 1. 2. 3. 4. 5. 6. 7. 8. 9. 前面四个都是写在always块内。 连续赋值没有RHS。
因为公司用的都是verilog/sv,所以虽然数字电路的综合结果都是组合/时序电路,但是verilog仿真器又确实会在乎所谓的阻塞和非阻塞赋值,没办法必须搞明白。 首先可以将delay control分为两类,一种是assign,一种是procedure assign. assign 就是最常见的assign. 其delay control有只有一种: assign #5 a = b; 这种写法...
Blocking assignment产生的条件 A problem with blocking assignments occurs when the RHS variable of one assignment in one procedural block is also the LHS variable of another assignment in another procedural block and both equations are scheduled to execute in the same simulation time step, such as o...
Introduction 1.當等號右邊的任何輸入發生改變時,continuous assignment敘述會再重新計算過。 2.等號兩邊之位元長度不必相同,不足會補0,過長會忽略。 3.不會合成出latch。 Reference
5.1.8 Assignment Verilog 支持两种赋值 :过程赋值(procedural) 和连续赋值(continuous)。过程赋值用于过程代码 initial, always, taskorfunction)中给reg 和 integer变量 time ealtimereal赋值, 而连续赋值一般给wire 变量赋值。 Always @(敏感表 敏感表要完整 如果不完整 将会引起仿真和综合结果不一致 always @(d...
“非阻塞赋值”为寄存器数据类型而设,所以只能被允许在程序块里面出现,比如initial块和always块。不允许持续性赋值(continuous assignments)。 为了举例说明,请看Verilog 编码例二: module fbosc2 (y1, y2, clk, rst); output y1, y2; input clk, rst; ...
Depending on the order of execution of the initial blocks, it could be zero and zero, or alternately zero and some other arbitrary uninitialized value. The $display statement will always execute after both assignment blocks have completed, due to the #1 delay. ...
endmodule//Example 4.5. Combined Net and Continuous Assignment. module modXor (AXorB, a, b); parameter size = 8, delay = 15;output [size-1:0] AXorB; input [size-1:0] a, b;wire [size-1:0] #delay AXorB = a ^ b; endmodule//Example 4.6. Net and Continuous Assignment Delays. ...
The wire network is similar to the wire we actually use. Its value can only be determined by continuous assignment, which is determined by the drive source connected to the right side of the assignment. The value of the wire net before initialization is x (trireg-type wire net is an exce...
lGuideline #8: Do not make assignments using #0 delays.//不要用#0的delay The Verilog "stratified event queue" stratified:分层的 仿真事件时序图。 stratified event queue可以分成4段:每段之中event的顺序是任意的,不定的。 active events: including ...