> http://forums.xilinx.com/xlnx/attachments/xlnx/EDK/27322/1/HighSpeedTrueRandomNumberGeneratorsinXilinxFPGAs.pdf
> 
I built a very wide version of this several months ago to do testing in the lab but it hasn't been tested yet.  I'll have to report back after my coworkers try it out.  You do have to instantiate LUT primitives to get it to synthesize.  I don't know why the app note didn't address this nor supply any example HDL.

On 05/04/2017 07:03 AM, colin wrote:
> On Thursday, May 4, 2017 at 11:44:54 AM UTC+1, kristoff wrote:
>> Hi,
>>
>> I am aware that the best way to create a seed (for random numbers) is
>> external hardware, but does anybody know any cheap-and-easy tricks to
>> generate a random-ish number on an FPGA.
>>
>>
>> Kristoff
>
> Read the LSB of the voltage monitoring in xilinx sysmon to get each bit of your number.
>
> Colin
>

I was going to suggest asynchronous ring oscillator, but yours is 
downright elegant.

-- 
Rob Gaddi, Highland Technology -- www.highlandtechnology.com
Email address domain is currently out of order.  See above to fix.

On 5/4/2017 11:33 AM, Mark Curry wrote:
> In article <u_idnX0HweEx3JbEnZ2dnUU7-IWdnZ2d@giganews.com>,
> Tim Wescott  <tim@seemywebsite.really> wrote:
>> On Thu, 04 May 2017 07:03:03 -0700, colin wrote:
>>
>>> On Thursday, May 4, 2017 at 11:44:54 AM UTC+1, kristoff wrote:
>>>> Hi,
>>>>
>>>> I am aware that the best way to create a seed (for random numbers) is
>>>> external hardware, but does anybody know any cheap-and-easy tricks to
>>>> generate a random-ish number on an FPGA.
>>>>
>>>>
>>>> Kristoff
>>>
>>> Read the LSB of the voltage monitoring in xilinx sysmon to get each bit
>>> of your number.
>>>
>>> Colin
>>
>> Or for sufficiently random request timing, keep a clock running and use
>> the clock value for the seed.
>>
>> Or combine the two.
>>
>> I seem to remember doing a web search on this a while back -- there are a
>> lot of papers, of varying degrees of technical soundness.
>
> Xilinx has many app notes on this - it's a common requests.
> Here's one I've read in the past, but there's others:
>
> http://forums.xilinx.com/xlnx/attachments/xlnx/EDK/27322/1/HighSpeedTrueRandomNumberGeneratorsinXilinxFPGAs.pdf

I thought this issue had been solved?

https://xkcd.com/221/

-- 

Rick C

In article <u_idnX0HweEx3JbEnZ2dnUU7-IWdnZ2d@giganews.com>,
Tim Wescott  <tim@seemywebsite.really> wrote:
>On Thu, 04 May 2017 07:03:03 -0700, colin wrote:
>
>> On Thursday, May 4, 2017 at 11:44:54 AM UTC+1, kristoff wrote:
>>> Hi,
>>> 
>>> I am aware that the best way to create a seed (for random numbers) is
>>> external hardware, but does anybody know any cheap-and-easy tricks to
>>> generate a random-ish number on an FPGA.
>>> 
>>> 
>>> Kristoff
>> 
>> Read the LSB of the voltage monitoring in xilinx sysmon to get each bit
>> of your number.
>> 
>> Colin
>
>Or for sufficiently random request timing, keep a clock running and use 
>the clock value for the seed.
>
>Or combine the two.
>
>I seem to remember doing a web search on this a while back -- there are a 
>lot of papers, of varying degrees of technical soundness.

Xilinx has many app notes on this - it's a common requests.
Here's one I've read in the past, but there's others:

http://forums.xilinx.com/xlnx/attachments/xlnx/EDK/27322/1/HighSpeedTrueRandomNumberGeneratorsinXilinxFPGAs.pdf

Regards,

Mark

On Thu, 04 May 2017 07:03:03 -0700, colin wrote:

> On Thursday, May 4, 2017 at 11:44:54 AM UTC+1, kristoff wrote:
>> Hi,
>> 
>> I am aware that the best way to create a seed (for random numbers) is
>> external hardware, but does anybody know any cheap-and-easy tricks to
>> generate a random-ish number on an FPGA.
>> 
>> 
>> Kristoff
> 
> Read the LSB of the voltage monitoring in xilinx sysmon to get each bit
> of your number.
> 
> Colin

Or for sufficiently random request timing, keep a clock running and use 
the clock value for the seed.

Or combine the two.

I seem to remember doing a web search on this a while back -- there are a 
lot of papers, of varying degrees of technical soundness.

-- 
www.wescottdesign.com

On Thursday, May 4, 2017 at 11:44:54 AM UTC+1, kristoff wrote:
> Hi,
> 
> I am aware that the best way to create a seed (for random numbers) is 
> external hardware, but does anybody know any cheap-and-easy tricks to 
> generate a random-ish number on an FPGA.
> 
> 
> Kristoff

Read the LSB of the voltage monitoring in xilinx sysmon to get each bit of your number.

Colin

Hi,

I am aware that the best way to create a seed (for random numbers) is 
external hardware, but does anybody know any cheap-and-easy tricks to 
generate a random-ish number on an FPGA.


Kristoff