目录

一、前言

二、Logic Level distribution

2.1 logic level配置

2.2 Logic Level Distribution报告

2.3 Logic Level 报告详情查看

2.4 Route Distributions 报告详情查看

2.5 示例代码

---

一、前言

    ​在工程设计中，如果需要了解路径的逻辑级数，可以在report timing summary中找到对应的时序路径，查看时序路径的详情报告中有逻辑级数的信息，如下图

    ​这种方法查看有一个缺点，就是无法知道工程设计中逻辑级数的总体情况，这个时候就可以使用Report design analysis中的Include logic level distribution来查看

二、Logic Level distribution

2.1 logic level配置

    ​工程运行完Synthesize或implement时，进入菜单栏的“Reports”中，在“Reports->Report Design Analysis->Options”中，存在“Include logic level distribution”，默认不勾选，勾选后同时可以设置展示总的显示逻辑级数数量Number of paths，默认是1000条，表示最多只显示1000条，这1000条是所有路径中最差slack的1000条，不足1000条时按实际显示路径数显示。

2.2 Logic Level Distribution报告

    ​以Number of paths设置20为例，在Logic Level Distribution中将显示所有时序路径中最差的20条路径。注：logic level distribution只考虑setup路径。

左侧报告包含3类内容：

End Point Clock：根据所有时序路径中End Point Clock来划分

Requirement：展示的End point clock对应路径中最差的Requirement，以End point clock为clk1，逻辑级数为0的1条，逻辑级数为1的3条，逻辑级数为2的没有

查看逻辑级数为0路径的requirement

查看逻辑级数为1路径的requirement，在Logic level distribution中clk1选取的requirement为-2，即为所有路径requirement中的最小值

工程中各逻辑级数：此处时序路径数逻辑级数只有0级，1级和2级，下面对应的展示了各逻辑级数的路径数量，所有路径数量加起来即为设置的Number of paths值20

2.3 Logic Level 报告详情查看

在logic level distribution报告中，选中需要查看的路径，以下图clk2的逻辑级数为1的3条路径为例，见红框内，点击鼠标左键，弹出弹框

选择“Report Design Analysis on Timing Paths”，在原有的Design analysis窗口中打开报告，报告为setup path characteristics

选择“Report Timing on Timing Paths”，在新打开的Timing窗口中以时序报告路径的形式展现

在完成Implement后，选择“Select Timing Paths”，将会在Netlist窗口和device中显示该路径中的包含的cells和路径(白色高亮)

2.4 Route Distributions 报告详情查看

生成Report Design Analysis时如果勾选Routes，则可以生成Route Distributions报告，主要提供时序路径中完全布线的net数量

Routes数量表示时序路径上data path中属于fully routed的net数量，通常是和逻辑级数一致，如果时序路径属于起点或终点为port的，如recovery路径或设置了setup_output_delay的路径，则logic level值和routes会不一致

以上图的end point clock为clk2，数量为1的4为例，执行report timing on timing paths，时序报告中有一列Routes，显示了对应路径 routes的数量，图中都为1

执行select timing paths，在Net窗口会显示对应的routes名称，Route Status为Fully routed的才被考虑，如下图第1条net rst属于routed to a hierarchical port，则不会考虑进Routes Distribution中，因此路径的routes数量为1，level也为1。

Route Status为internally routed within one site也不会被统计到routes中

​下面的路径中logic level为1，route数量为2

2.5 示例代码

module logic_level(CLKIN1,CLKIN2,CLKINSEL,CLKFBIN,CLKFBOUT,clk1,clk2,rst,d1,d2,S,i_bus,o_bus,bus_clk2,out_syn,out_asyn,and_out,o_case);
input CLKIN1,CLKIN2,CLKINSEL,CLKFBIN,clk1,clk2,rst,d1,d2,S;
input [4:0] i_bus;
output reg [4:0] o_bus,bus_clk2;
output out_syn,out_asyn,and_out,CLKFBOUT;
reg ff1,ff2,ff_asyn,ff_syn,ff_and;
reg ff_case;
output reg o_case;
reg [4:0] bus;
wire sum12,and_c,CLKOUT0,CLKOUT1;
wire [4:0] bus_c;
wire o_bufgmux,ffcase_n;PLLE2_ADV #(.BANDWIDTH("OPTIMIZED"),  // OPTIMIZED, HIGH, LOW.CLKFBOUT_MULT(8),        // Multiply value for all CLKOUT, (2-64).CLKFBOUT_PHASE(0.0),     // Phase offset in degrees of CLKFB, (-360.000-360.000).// CLKIN_PERIOD: Input clock period in nS to ps resolution (i.e. 33.333 is 30 MHz)..CLKIN1_PERIOD(0.0),.CLKIN2_PERIOD(0.0),// CLKOUT0_DIVIDE - CLKOUT5_DIVIDE: Divide amount for CLKOUT (1-128).CLKOUT0_DIVIDE(1),.CLKOUT1_DIVIDE(2),.CLKOUT2_DIVIDE(4),.CLKOUT3_DIVIDE(5),.CLKOUT4_DIVIDE(1),.CLKOUT5_DIVIDE(1),// CLKOUT0_DUTY_CYCLE - CLKOUT5_DUTY_CYCLE: Duty cycle for CLKOUT outputs (0.001-0.999)..CLKOUT0_DUTY_CYCLE(0.4),.CLKOUT1_DUTY_CYCLE(0.5),.CLKOUT2_DUTY_CYCLE(0.5),.CLKOUT3_DUTY_CYCLE(0.5),.CLKOUT4_DUTY_CYCLE(0.5),.CLKOUT5_DUTY_CYCLE(0.5),// CLKOUT0_PHASE - CLKOUT5_PHASE: Phase offset for CLKOUT outputs (-360.000-360.000)..CLKOUT0_PHASE(0.0),.CLKOUT1_PHASE(0.0),.CLKOUT2_PHASE(0.0),.CLKOUT3_PHASE(0.0),.CLKOUT4_PHASE(0.0),.CLKOUT5_PHASE(0.0),.COMPENSATION("EXTERNAL"),   // ZHOLD, BUF_IN, EXTERNAL, INTERNAL.DIVCLK_DIVIDE(1),        // Master division value (1-56)// REF_JITTER: Reference input jitter in UI (0.000-0.999)..REF_JITTER1(0.0),.REF_JITTER2(0.0),.STARTUP_WAIT("FALSE")    // Delay DONE until PLL Locks, ("TRUE"/"FALSE"))PLLE2_ADV_inst (// Clock Outputs: 1-bit (each) output: User configurable clock outputs.CLKOUT0(CLKOUT0),   // 1-bit output: CLKOUT0.CLKOUT1(CLKOUT1),   // 1-bit output: CLKOUT1.CLKOUT2(CLKOUT2),   // 1-bit output: CLKOUT2// Feedback Clocks: 1-bit (each) output: Clock feedback ports.CLKFBOUT(CLKFBOUT), // 1-bit output: Feedback clock// Clock Inputs: 1-bit (each) input: Clock inputs.CLKIN1(CLKIN1),     // 1-bit input: Primary clock.CLKIN2(CLKIN2),     // 1-bit input: Secondary clock// Control Ports: 1-bit (each) input: PLL control ports.CLKINSEL(CLKINSEL), // 1-bit input: Clock select, High=CLKIN1 Low=CLKIN2.RST(rst),           // 1-bit input: Reset// Feedback Clocks: 1-bit (each) input: Clock feedback ports.CLKFBIN(CLKFBIN)    // 1-bit input: Feedback clock);// End of PLLE2_ADV_inst instantiationalways@(posedge CLKOUT0,negedge rst)if(!rst)beginff1<=1'b0;ff2<=1'b0;endelse beginff1<=d1;ff2<=d2;endassign sum12=ff1+ff2;
always@(posedge CLKOUT1,negedge rst)if(!rst)ff_syn<=1'b0;else beginff_syn<=sum12;end
assign out_syn=ff_syn;always@(posedge clk1,negedge rst)if(!rst)ff_asyn<=1'b0;else beginff_asyn<=sum12;end
assign out_asyn=ff_asyn;
assign and_c=ff_asyn&d1;always@(posedge clk1,negedge rst)if(!rst)ff_and<=1'b0;else beginff_and<=and_c;end
assign and_out=ff_and;always@(posedge clk1,negedge rst)if(!rst)bus<=5'b0;else beginbus<=i_bus+1'b1;end
assign bus_c=bus+d2;
always@(*)begino_bus=bus;end
always@(posedge clk2,negedge rst)if(!rst)bus_clk2<=5'b0;else beginbus_clk2<=bus_c+d1;end//set_case_analysisBUFGMUX #()BUFGMUX_inst (.O(o_bufgmux),   // 1-bit output: Clock output.I0(CLKIN1), // 1-bit input: Clock input (S=0).I1(CLKIN2), // 1-bit input: Clock input (S=1).S(S)    // 1-bit input: Clock select);always@(posedge o_bufgmux,negedge rst)if(!rst)ff_case<=1'b0;else beginff_case<=d1;end
assign ffcase_n=!ff_case;always@(posedge o_bufgmux,negedge rst)if(!rst)o_case<=1'b0;else begino_case<=ffcase_n;endendmodule 

约束

//创建主时钟和生成时钟
create_clock -period 10.000 -name clkin1 -waveform {0.000 5.000} -add [get_ports CLKIN1]
create_clock -period 5.000 -name clkin2 -waveform {0.000 2.500} -add [get_nets CLKIN2]
create_clock -period 4.000 -name clk2 -waveform {0.000 2.000} -add [get_ports clk2]
create_clock -period 4.000 -name clk1 -waveform {0.000 2.000} -add [get_ports clk1]
create_generated_clock -name gen_clk -source [get_pins PLLE2_ADV_inst/CLKOUT1] -multiply_by 2 -add -master_clock clkin2 [get_pins PLLE2_ADV_inst/CLKOUT0]
set_input_jitter [get_clocks clk2] 0.500
set_clock_latency -clock [get_clocks clk2] 0.333 [get_pins {bus_reg[1]/D}]
set_system_jitter 0.009
set_clock_uncertainty 0.500 [get_clocks clk1]//设置时钟组和总线偏斜
set_clock_groups -name clkin1_group -asynchronous -group [get_clocks clkin1]
set_bus_skew -from [get_cells {{bus_reg[0]} {bus_reg[1]} {bus_reg[2]} {bus_reg[3]} {bus_reg[4]}}] -to [get_cells {{bus_clk2_reg[0]} {bus_clk2_reg[1]} {bus_clk2_reg[2]} {bus_clk2_reg[3]} {bus_clk2_reg[4]}}] 0.550
set_input_delay -clock [get_clocks clk1] 1.111 [get_ports {d1 d2 {i_bus[0]} {i_bus[1]} {i_bus[2]} {i_bus[3]} {i_bus[4]} rst}]
set_output_delay -clock [get_clocks clk2] 0.222 [get_ports {and_out {o_bus[0]} {o_bus[1]} {o_bus[2]} {o_bus[3]} {o_bus[4]} out_asyn out_syn}]//设置时序例外分析
set_false_path -setup -from [get_pins {bus_reg[2]/C}] -to [get_pins {bus_clk2_reg[4]/D}]
set_max_delay -from [get_pins {bus_reg[1]/C}] 2.000
set_min_delay -from [get_pins {bus_reg[0]/C}] 0.500
set_external_delay -from [get_ports CLKFBOUT] -to [get_ports CLKFBIN] 0.444
set_multicycle_path -from [get_pins {bus_reg[0]/C}] -to [get_pins {bus_clk2_reg[2]/D}] 2
set_disable_timing [get_cells {bus_reg[3]}]//设置时序断言
set_case_analysis 1 [get_ports S]
set_data_check -from [get_pins {bus_reg[2]/C}] -to [get_pins {bus_reg[2]/Q}] 0.333 -clock [get_clocks clk2]
set_clock_sense -positive -clocks [get_clocks clk1] [get_pins ff_asyn_reg/C]
group_path -name {group_path} -weight 1.000 -from [get_ports {d1 d2}]