如何在vhdl中声明浮点数

马赫什，
如果您尝试将高频时钟分频为较低频率的时钟，则会提出错误的问题。
要在硬件中划分时钟，可以实现计数器。
计数器值与整数（非浮点）进行比较，比较用于复位计数器并生成输出时钟边沿。
- 鲍勃埃尔金德
签名：新手的自述文件在这里：http：//forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369总结：1。
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以下为原文

Mahesh,
 
If you are trying to divide a high frequency clock to a lower frequency clock, you are asking the wrong questions.
 
To divide a clock, in hardware, you implement a counter.  The counter value is compared to an integer (not floating point), and the comparison is used to reset the counter and generate an output clock edge.
 
- Bob Elkind
SIGNATURE:
README for newbies is here: http://forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369

Summary:
1. Read the manual or user guide.  Have you read the manual? Can you find the manual?
2. Search the forums (and search the web) for similar topics.
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4. Do not post a new topic or question on someone else's thread, start a new thread!
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嗨，  
我试图将高频时钟分成低频。我必须从GUI输入.GUI会给我时间段。我必须计算频率。然后我必须将HIGH频率除以计算的频率。所以我
我在20微秒的步骤中将1微秒增加到1毫秒。所以基于那个时间段，我在我的代码中计算频率。所以我必须首先声明它。然后这次我必须要...
感谢你，Mahesh Hegde。



以下为原文

Hi,      
        I am trying to divide high frequency clock into low frequency.I have to take the input from GUI.GUI will give me time period.I have to calculate the frequency .Then i have to divide HIGH frequency by the calcuted frequency..So i am incrementing 1microsecond to 1 milisec in the step of 20microsecond.So based on that time period i am calculating frequency in my code.So i have to declare it first.then this time i have to incriment..
Thanks You in Advance,
Mahesh Hegde.

maheshhegde写道：
嗨，  
我试图将高频时钟分成低频。我必须从GUI输入.GUI会给我时间段。我必须计算频率。然后我必须将HIGH频率除以计算的频率。所以我
我在20微秒的步骤中将1微秒增加到1毫秒。所以基于那个时间段，我在我的代码中计算频率。所以我必须首先声明它。然后这次我必须要...
那么你的问题是什么？
我强烈认为您只需要一个可调节间隔的单个时钟启用。
那是对的吗？
如果没有，请解释您需要的分频器。
你知道如何实现一个控制时钟启用的计数器吗？
你是什​​么意思“GUI”，这是什么GUI？
你写了吗？
它是否创建包含分频器的VHDL文件？
或者它是一个在计算机上运行的程序，它向FPGA发送命令？
如果您的问题太模糊，您希望我们如何回答您的问题？
在我们帮助您之前，我们需要更详细的信息。
阿德里安
请在询问之前先查询您的问题。如果有人回答您的问题，请在“接受为解决方案”标记该帖子。
如果你看到一个特别好的和信息丰富的帖子，考虑给它Kudos（左边的星）。



以下为原文

 

maheshhegde wrote:
Hi,      
        I am trying to divide high frequency clock into low frequency.I have to take the input from GUI.GUI will give me time period.I have to calculate the frequency .Then i have to divide HIGH frequency by the calcuted frequency..So i am incrementing 1microsecond to 1 milisec in the step of 20microsecond.So based on that time period i am calculating frequency in my code.So i have to declare it first.then this time i have to incriment..

So what's your question?
 
 
I strongly suppose that all you need is a single clock enable at adjustable intervals. Is that correct? If not, please explain what you need the frequency divider for.
 
Do you know how to implement a counter that controls your clock enable? And what do you mean by "GUI", what GUI is that? Did you write it? Does it create a VHDL file that contains the frequency divider? Or is it a program, running on a computer, which sends commands to the FPGA?
 
How do you expect us to answer your question if your question is so vague? We need more detailed information before we can help you.
 
 
Adrian

Please google your question before asking it.
If someone answers your question, mark the post with "Accept as solution". If you see a particularly good and informative post, consider giving it Kudos (the star on the left).

马赫什，
只需实现整数除法。
除非你想暴力破解它，否则就需要一台状态机。
你的状态机技能有多好？
你还记得如何从小学那里做长期分工吗？
同样的事情......只是二进制而不是十进制。
- 鲍勃埃尔金德
签名：新手的自述文件在这里：http：//forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369总结：1。
阅读手册或用户指南。
你读过手册了吗？
你能找到手册吗？2。
搜索论坛（并搜索网页）以寻找类似的主题。
不要在多个论坛上发布相同的问题。
不要在别人的主题上发布新主题或问题，开始新的主题！5。
学生：复制代码与学习设计不同.6“它不起作用”不是一个可以回答的问题。
提供有用的详细信息（请与网页，数据表链接）.7。
您的代码中的评论不需要支付额外费用。
我没有支付论坛帖子的费用。
如果我写一篇好文章，那么我一无所获。



以下为原文

Mahesh,
 
Just implement an integer divide.  Unless you want to brute force it, that will require a state machine.
 
How good are your state machine skills?
 
Do you remember how to do long-hand divide from grade school?  Same thing...  just binary instead of decimal.
 
- Bob Elkind
SIGNATURE:
README for newbies is here: http://forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369

Summary:
1. Read the manual or user guide.  Have you read the manual? Can you find the manual?
2. Search the forums (and search the web) for similar topics.
3. Do not post the same question on multiple forums.
4. Do not post a new topic or question on someone else's thread, start a new thread!
5. Students: Copying code is not the same as learning to design.
6 "It does not work" is not a question which can be answered. Provide useful details (with webpage, datasheet links, please).
7. You are not charged extra fees for comments in your code.
8. I am not paid for forum posts.  If I write a good post, then I have been good for nothing.

嗨Mahesh，
当你有一个时间段，那么你也可以计算所有其他值作为时间段。
无需将其转换为频率值。
你应该试着打破算法，而不是盲目的直接方法
到了充分利用你的资源的地步。
计算就像
Tout = 1 /（Fhigh /（1 / Tlow））太复杂了。
Tout =大腿/ Tlow简单得多。
只需要两分钟的简单代数即可完成这一步。
此外，如果你知道你要用固定步骤增加某些东西（例如20 us）
你已经只有有限的结果范围，可以用整数轻松处理（不是VHDL数据类型只是数学参考）。
所以不需要任何浮点内容。
GUI通过某些接口将一些值（例如，时间段）发送到FPGA中。
这个值的数据格式是什么？
为什么它会发送一些你必须在FPGA中修改的值。
为什么GUI尚未进行计算，只有最终需要的启动周期被转移到FPGA，准备写入某些寄存器，甚至计数器本身。
有一个很好的综合 
Eilert



以下为原文

Hi Mahesh,
when you got a time period, then you can calculate all other values also as time periods.
No need to convert this into frequency values.
Instead of a mindless straightforward approach you should try to break down the algorithm
to a point that makes best use of your ressources.
A calculation like
 
Tout = 1/(Fhigh/(1/Tlow))  is much too complicated.
 
Tout = Thigh/Tlow is a lot simpler.
And it takes just two minutes of simple algebra to make that step.
 
Also, If you know that you are going to increment something with a fixed step(e.g. 20 us)
you already have only a limited range of results, which can easily be handled with integers (not the VHDL data type just the mathematical reference).
So there's no need for floating point stuff whatsoever.
 
A GUI sends some values (e.g. a time period) over some interface into the FPGA.
What's the data format of this value?
And why is it sending some value that you have to modify in the FPGA.
Why is that calculation not already made by the GUI and only the finally wanted Starting period is transferd to the FPGA ready made to be written to some registers, or even the counter itself.
 
Have a nice synthesis
   Eilert

那么你的问题是什么？
阿德里安写道，
我强烈认为您只需要一个时钟启用
可调间隔。
那是对的吗？
如果没有，请解释一下你的情况
需要分频器。
你知道如何实现一个控制你的时钟的计数器
启用？
你是什​​么意思“GUI”，这是什么GUI？
你写了吗？
它？
它是否创建包含分频器的VHDL文件？
要么
它是一个在计算机上运行的程序，它向命令发送命令
FPGA？
如果您的问题如此，您希望我们如何回答您的问题？
模糊？
在我们帮助您之前，我们需要更详细的信息。 
GUI将向FPGA发送命令。应该是增量之间的延迟？我的输入时钟频率是30 Mhz。如果用户说增量之间需要20milisec延迟。我必须将30 Mhz clk除以600000.如何确定数字（600000）
或者数字是多少）？
感谢你，Mahesh Hegde。



以下为原文

So what's your question?
 
 
 
 Adrian wrote,
 
I strongly suppose that all you need is a single clock enable at adjustable intervals. Is that correct? If not, please explain what you need the frequency divider for.
 
Do you know how to implement a counter that controls your clock enable? And what do you mean by "GUI", what GUI is that? Did you write it? Does it create a VHDL file that contains the frequency divider? Or is it a program, running on a computer, which sends commands to the FPGA?
 
How do you expect us to answer your question if your question is so vague? We need more detailed information before we can help you.
 
 
           GUI will send command to FPGA.What should be the delay between increment?My input clock frequency is 30 Mhz.If user says 20milisec delay is required between increments.I have to divide the 30 Mhz clk by 600000.How to decide number(600000 or what is the number)?
 
 
Thanks You in Advance,
Mahesh Hegde.

马赫什，
如果源时钟频率是固定的（例如30 MHz），则完全避免除法功能很简单。
如果GUI发送值20（20 mS），则将GUI值乘以常数整数值：30,000（d）或7530（h）。
乘法很简单，乘以常数甚至更简单。
乘法的乘积（结果）是输出时钟周期为20 mS时的源时钟（30 MHz）时钟周期数。
将20（d）乘以30,000（d）的结果是60,000（d）或927C0（h）。
时钟周长为927C0（h），频率为30MHz，频率为20mS。
这对你有意义吗，Mahesh？
你现在是否过了“浮点”问题，并对整数感到满意？
- 鲍勃埃尔金德
签名：新手的自述文件在这里：http：//forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369总结：1。
阅读手册或用户指南。
你读过手册了吗？
你能找到手册吗？2。
搜索论坛（并搜索网页）以寻找类似的主题。
不要在多个论坛上发布相同的问题。
不要在别人的主题上发布新主题或问题，开始新的主题！5。
学生：复制代码与学习设计不同.6“它不起作用”不是一个可以回答的问题。
提供有用的详细信息（请与网页，数据表链接）.7。
您的代码中的评论不需要支付额外费用。
我没有支付论坛帖子的费用。
如果我写一篇好文章，那么我一无所获。



以下为原文

Mahesh,
 
If your source clock frequency is fixed (e.g. 30 MHz), it's simple to avoid a divide function entirely.
 
If the GUI sends a value of 20 (for 20 mS), multiply the GUI value by a constant integer value: 30,000(d) or 7530(h).  Multiplies are simple, and multiplying by a constant is even simpler.  The product (result) of the multiply is the number of source clock (30 MHz) clock ticks in an output clock period of 20 mS.
 
The result of multiplying 20(d) by 30,000(d) is 60,000(d) or 927C0(h).   There are 927C0(h) clock ticks, at 30MHz, in 20mS.
 
Does this make sense to you, Mahesh?  Are you now past the "floating point" question, and satisfied with integers?
 
- Bob Elkind
SIGNATURE:
README for newbies is here: http://forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369

Summary:
1. Read the manual or user guide.  Have you read the manual? Can you find the manual?
2. Search the forums (and search the web) for similar topics.
3. Do not post the same question on multiple forums.
4. Do not post a new topic or question on someone else's thread, start a new thread!
5. Students: Copying code is not the same as learning to design.
6 "It does not work" is not a question which can be answered. Provide useful details (with webpage, datasheet links, please).
7. You are not charged extra fees for comments in your code.
8. I am not paid for forum posts.  If I write a good post, then I have been good for nothing.

maheshhegde写道：
嗨， 
我想声明浮点范围从1微秒到1毫秒。＆amp;
1 milisec到1秒。如何使用VHDL声明它。我必须在20microsec从1 milisec到1 milisec的步骤中实施。请帮助我.........
哇，你的家庭作业变得有趣了。
----------------------------是的，我这样做是为了谋生。



以下为原文

 

maheshhegde wrote:
Hi,
     I want to declare floating point range from 1 microsecond to 1 milisec.& 1 milisec to 1 second.How to declare it by using VHDL.I have to incriment in the step of 20microsec from 1 milisec to 1 milisec.Please help me.........

Wow, your homework assignments are getting interesting.
 
----------------------------Yes, I do this for a living.