一Vhdl语言中
1 提示:VHDL syntax error:expected choice in case statement
Case语句中没覆盖到所有的情况,要加whe n others=> null;
二.在verge hdl语句中
在QuartusII下进行编译和仿真的时候,会出现一堆warning,有的可以忽略,有的却需要注意,虽然按F1可以了解关于该警告的帮助,但有时候帮助解释的仍然不清楚,大家群策群力,把自己知道和了解的一些关于警告的问题都说出来讨论一下,免得后来的人走弯路?
下面是我收集整理的一些,有些是自己的经验,有些是网友的,希望能给大家一点帮助,如有不对的地方,请指正,如果觉得好,请版主给点威望吧,谢谢
1. Found clock-sensitive change during active clock edge at time
原因:vector source file中时钟敏感信号(如:数据,允许端,清零,同步加载等)在时钟
的边缘同时变化。而时钟敏感信号是
不能在时钟边沿变化的。其后果为导致结果不正确。
措施:编辑vector source file
2. Verilog HDL assignment warning at
原因:在HDL设计中对目标的位数进行了设定,如:reg[4:0] a;而默认为32位,将位数裁定到合适
的大小
措施:如果结果正确,无须加以修正,如果不想看到这个警告,可以改变设定的位数
3. AII reachable assignments to data_out(10) assign 'O', register removed by optimization
原因:经过综合器优化后,输出端口已经不起作用了
4. Follow ing 9 pi ns have nothing, GND, or VCC drivi ng datai n port -- cha nges to this conn ectivity may cha nge fitt ing results
原因:第9脚,空或接地或接上了电源
措施:有时候定义了输出端口,但输出端直接赋’0'便会被接地,赋’1'接电源。如果你
的设计中这些端口就是这样用的,那便可以不理会这些warni ng
5. F ound pins functioning as un defi ned clocks an d/or memory en ables
原因:是你作为时钟的PIN没有约束信息。可以对相应的PIN做一下设定就行了。主要是指
你的某些管脚在电路当中起到了时钟管脚的
作用,比如flip-flop的clk管脚,而此管脚没有时钟约束,因此QuartusII把"elk”作为未定
义的时钟。
措施:如果clk不是时钟,可以加"not clock”的约束;如果是,可以在clock setting当中加入;在某些对时钟要求不很高的情况下,可以忽略此警告或在这里修改:Assig nme nts>Timi ng
an alysis sett in gs... >ln dividual clocks...>...
注意在Applies to node中只用选择时钟引脚一项即可,required fmax 一般比所要求频率高5% 即
可,无须太紧或太松。
6. Ti ming characteristics of device EPM570T144C5 are prelim inary
原因:因为MAXII是比較新的元件在Quartusll中的時序並不是正式版的,要等Service Pack
措施:只影响Quartus的Waveform
7. Warning: Clock latency analysis for PLL offsets is supported for the current device family, but is not en abled
扌昔施:将sett ing 中的tim ing Requireme nts&Opti on-->More Timing Sett in g-->sett in g-->E nable Clock Latency 中的on 改成OFF
8. F ound clock high time violatio n at 14.8 ns on register
"|cou nter|lpm_cou nter:cou nt1_rtl_O|dffs[11]"
原因:违反了steup/hold时间,应该是后仿真,看看波形设置是否和时钟沿符合steup/hold 时间
措施在中间加个寄存器可能可以解决问题
9. war ning: circuit may not operate.detected 46 non-operati onal paths clocked by clock clk44 with clock skew larger tha n data delay
原因:时钟抖动大于数据延时,当时钟很快,而if等类的层次过多就会出现这种问题,但这个问题多是在器件的最高频率中才会出现
措施:sett in g-->ti ming Requireme nts&Opti on s-->Default required fmax 改小一些,如改至U
50MHZ
10. Desig n contains
原因:输入引脚没有驱动逻辑(驱动其他引脚),所有的输入引脚需要有输入逻辑措施:如果这种情况是故意的,无须理会,如果非故意,输入逻辑驱动.
11. Warning : Found clock high time violation at 8.9ns on node 'TEST3.CLK'
原因:FF中输入的PLS的保持时间过短措施:在FF中设置较高的时钟频率
12. War ning: Found 10 no de(s) in clock paths which may be acting as ripple an d/or gated clocks -no de(s) an alyzed as buffer(s) result ing in clock skew
原因:如果你用的CPLD只有一组全局时钟时,用全局时钟分频产生的另一个时钟在布线中当作信号处理,不能保证低的时钟歪斜(SKEW>会造成在这个时钟上工作的时序电路不可靠,甚至每次布线产生的问题都不一样。
措施:如果用有两组以上全局时钟的芯片,可以把第二个全局时钟作为另一个时钟用,可以
解决这个问题。FPGA
13. Critical Warning: Timing requirements were not met. See Report window for details.
原因:时序要求未满足,
措施:双击Compilation Report-->Time Analyzer--> 红色部分(如clock setup:'clk'等)-->左键单击list path,查看fmax的SLACK REPOR再根据提示解决,有可能是程序的算法问题或fmax设置问题
14. War ning: Can't find sig nal in vector source in put pin |whole|clk10m
原因:这个时因为你的波形仿真文件(vector source file )中并没有把所有的输入信号(input pin)加进去,对于每一个输入都需要有激励源的
15. C an't achieve minimum setup and hold requirement
原因:时序分析发现一定数量的路径违背了最小的建立和保持时间,与时钟歪斜有关,一般是由于多时钟引起的
措施:利用Compilation Report-->Time Analyzer-->红色部分(如clock hold:'clk'等),在slack 中观察是hold time 为负值还是setup time 为负值,然后在:Assignment-->Assignment Editor-->To中增加时钟名(from node finder),Assignment Name中增加和多时钟有关的Multicycle 和Multicycle Hold 选项,如hold time 为负,可使Multicycle hold 的值>multicycle, 如设为2和1。
16: Can't an alyze */*.v is miss ing
原因:试图编译一个不存在的文件,该文件可能被改名或者删除了
措施:不管他,没什么影响
17. War ning: Can't find sig nal in vector source in put pin |whole|clk10m
原因:因为你的波形仿真文件( vector source file )中并没有把所有的输入信号(in put pi n) 加进去,对于每一个输入都需要有激励源的
18. Error: Can't name logic function scfifo0 of instance "inst" -- function has same name as current desig n file
原因:模块的名字和project的名字重名了
措施:把两个名字之一改一下,一般改模块的名字
19. War ning: Using desig n , which is not specified as a desig n the curre nt project, but contains definitions for 1 design units and 1 entities in project Info: Found entity 1: Ipm_fifo0
原因:模块不是在本项目生成的,而是直接copy 了别的项目的原理图和源程序而生成的,
而不是用QUARTUS将文件添加进本项目
措施:无须理会,不影响使用
20. Ti ming characteristics of device
原因:目前版本的QuartusII只对该器件提供初步的时序特征分析
措施:如果坚持用目前的器件,无须理会该警告。关于进一步的时序特征分析会在后续版本
的Quartus得到完善。
21. Timing Analysis does not support the analysis of latches as synchronous elements for the curre ntly selected device family
原因:用analyze_latches_as_synchronous_elements setting 可以让Quaruts II 来分析同步锁存,
但目前的器件不支持这个特性
措施:无须理会。时序分析可能将锁存器分析成回路。但并不一定分析正确。其后果可能会
导致显示提醒用户:改变设计来消除锁存器,但实际其实无关紧要
22. W ar nin g:F ound xx output pins without output pin load capacita nee assig nment
原因:没有给输出管教指定负载电容
解决方法:该功能用于估算TCO和功耗,可以不理会,也可以在Assignment Editor中为相应
的输出管脚指定负载电容,以消除警告
1 Warning: VHDL Process Stateme nt warning at ran dom.vhd(18): sig nal reset is in stateme nt, but is not in sen sitivity list
----没把sin gal 放到process ()中
2 Warning: Found pins ing as un defi ned clocks an d/or memory en ables
Info: Assu ming node CLK is an un defi ned clock
-=-----可能是说设计中产生的触发器没有使能端
3 Error: VHDL In terface Declarati on error in clk_ge n. vhd(29): in terface object "clk_sca n" of mode out cannot be read. Change object mode to buffer or ino ut.
--- 信号类型设置不对,out当作buffer来定义
4 Error: Node in sta nee "clk_ge n1" in sta ntiates un defi ned en tity "clk_ge n"
--- 引用的例化元件未定义实体——en tity "clk_ge n"
5 Warning: Found 2 no de(s) in clock paths which may be acting as ripple an d/or gated clocks -no de(s) an alyzed as buffer(s) result ing in clock skew
Info: Detected ripple clock "clk_ge n: clk_ge n1|clk_i ncr" as buffer
Info: Detected ripple clock "clk_ge n: clk_ge n1|clk_sca n" as buffer
6 Warning: VHDL Process Statement warning at ledmux.vhd(15): signal or variable "dataout" may not be assig ned a new in every possible path through the Process Stateme nt. Signal or variable "dataout" holds its previous in every path with no new assignment, which may create a comb in ati on al loop in the curre nt desig n.
7 Warning: VHDL Process Stateme nt warning at divider_10.vhd(17): sig nal "c nt" is read in side the Process Stateme nt but isn't in the Process Stateme nt's sen sivitity list
-----缺少敏感信号
8 Warning: No clock tran siti on on "coun ter_bcd7:co un ter_co un ter_clk|q_sig[3]" register
9 Warning: Reduced register "co un ter_bcd7:co un ter_co un ter_clk|q_sig[3]" with stuck clock port to stuck GND
10 Warning: Circuit may not operate. Detected 1 non-operational path(s) clocked by clock "class[1]" with clock skew larger than data delay. See Compilation Report for details.
11 Warning: Circuit may not operate. Detected 1 non-operati onal path(s) clocked by clock "sig n" with clock skew larger tha n data delay. See Compilati on Report for details.
12 Error: VHDL error at counter_clk.vhd(90): actual port "class" of mode "in" cannot be associated with formal port "class" of mode "out"
------两者不能连接起来
13 Warning: Ignored node in vector source file. Can't find corresponding node name "class_sig[2]" in desig n.
-- 没有编写testbench文件,或者没有编辑输入变量的值testbench里是元件申明和映射
14 Error: VHDL Bin di ng In dicati on error at freqdetect_top.vhd(19): port "class" in desig n en tity does not have std_logic_vector type that is specified for the same gen eric in the associated comp onent
---在相关的元件里没有当前文件所定义的类型
15 Error: VHDL error at ton gbu.vhd(16): can't infer register for sig nal "gate" because sig nal does not hold its outside clock edge
16 Warning: Found clock high time violati on at 1000.0 ns on register
"|fc oun ter|lpm_co un ter:temp_rtl_0|dffs[4]"
17 Warning: Compiler packed, optimized or syn thesized away node "temp[19]". Ig nored vector source .
---"temp[19]"被优化掉了
18 Warning: Reduced register "gate~reg0" with stuck data_in port to stuck GND
19 Warning: Desig n contains 2 in put pin(s) that do not drive logic
Warning: No output depe ndent on in put pin "elk"
Warning: No output depe ndent on in put pin "sig n"
------输出信号与输入信号无关,
20 Warning: Found clock high time violation at 16625.0 ns on register "|impulcomp|gate1"
21 Error: VHDL error at impulcomp.vhd(19): can't implement clock enable condition specified using binary operator "or"
22 Error: VHDL Association List error at period_counter.vhd(38): actual parameter assigned to formal parameter "alarm", but formal parameter is not declared
---- 连接表错误,形参"alarm"赋值给实参,形参没定义,可能是形参与实参的位置颠倒了,规定形参在实参之前。
23 Error: Ignored con struct behavier at period_co un ter.vhd(15) because of previous errors
-------------- 因为前一个错误而导致的错误
24 Error: VHDL error at period_co un ter.vhd(38): type of ide ntifier "alarm" does not agree with its usage as std_logic type
---------------------- "alarm"的定义类型与使用的类型不一致
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 con sta nt drivers for n et "data in _reg[22]" at shift_reg.vhd(19)
27 can't i nfer register for sig nal "num [0]" because sig nal does not hold its outside clock edge
28Error: Can't elaborate top-level user hierarchy
29 Error: Can't resolve multiple con sta nt drivers for n et "cs_i n" at led_key.vhd(32) -------- 有两个以上赋值语句,不能确定" cs_in”的值,
30 Warning: Ignored node in vector source file. Can't find corresp onding node n ame "over" in desig n.
--------- 在源文件中找不到对应的节点“over ”。
31 Error: Can't access JTAG chain
无法找到下载链
32 Info: Assu ming node "clk" is an un defi ned clock
1.Found clock-sensitive change during active clock edge at time
原因:vector source file中时钟敏感信号(如:数据,允许端,清零,同步加
载等)在时钟的边缘同时变化。而时钟敏感信号是不能在时钟边沿变化的。其后
果为导致结果不正确。
措施:编辑vector source HDL assignment warning at
with size
原因:在HDL设计中对目标的位数进行了设定,如:reg[4:0] a;而默认为32位,
将位数裁定到合适的大小
措施:如果结果正确,无须加以修正,如果不想看到这个警告,可以改变设定的位数
3. All reachable assig nments to data_out(10) assig n '0', register removed by optimizati on
原因:经过综合器优化后,输出端口已经不起作用了
4. Following 9 pins have nothing, GND, or VCC driving datain port -
cha nges to this conn ectivity may cha nge fitt ing results
原因:第9脚,空或接地或接上了电源
措施:有时候定义了输出端口,但输出端直接赋’0'便会被接地,赋’1'接电源。
如果你的设计中这些端口就是这样用的,那便可以不理会这些warni ng
5. F ound pins ing as un defi ned clocks an d/or memory en ables
原因:是你作为时钟的PIN没有约束信息。可以对相应的PIN做一下设定就行了。
主要是指你的某些管脚在电路当中起到了时钟管脚的作用,比如flip-flop的clk
管脚,而此管脚没有时钟约束,因此Quartusll把"clk”作为未定义的时钟。
措施:如果clk不是时钟,可以加"not clock ”的约束;如果是,可以在clock
setting当中加入;在某些对时钟要求不很高的情况下,可以忽略此警告或在这
里修改:Assig nmen ts>Ti ming an alysis sett in gs... >ln dividual clocks...〉...
6. Ti ming characteristics of device EPM570T144C5 are prelim inary
原因:因为MAXII是比較新的元件在Quartusll中的時序并不是正式版的,要
等Service Pack
措施:只影响Quartus的Waveform
7. War ning: Clock late ncy an alysis for PLL offsets is supported for the curre nt device family, but is not en abled
措施:将setting 中的timing Requirements&Option-->More Timing Sett in g-->setti ng-->E nable Clock Late ncy 中的on 改成OFF
8. Found clock high time violation at 14.8 ns on register
"|cou nter|lpm_cou nter:cou nt1_rtl_0|dffs[11]"
原因:违反了steup/hold时间,应该是后仿真,看看波形设置是否和时钟沿符
合steup/hold 时间
措施:在中间加个寄存器可能可以解决问题
9. war ning: circuit may not operate.detected 46 non-operati onal
paths clocked by clock clk44 with clock skew larger tha n data delay
原因:时钟抖动大于数据延时,当时钟很快,而if等类的层次过多就会出现这种问题,但这个问题多是在器件的最高频率中才会出现
措施:sett in g-->tim ing Requireme nts&Opti on s-->Default required
fmax改小一些,如改到50MHZ