Site Home   Archive Home   FAQ Home   How to search the Archive   How to Navigate the Archive   
Compare FPGA features and resources   

Threads starting:
1994JulAugSepOctNovDec1994
1995JanFebMarAprMayJunJulAugSepOctNovDec1995
1996JanFebMarAprMayJunJulAugSepOctNovDec1996
1997JanFebMarAprMayJunJulAugSepOctNovDec1997
1998JanFebMarAprMayJunJulAugSepOctNovDec1998
1999JanFebMarAprMayJunJulAugSepOctNovDec1999
2000JanFebMarAprMayJunJulAugSepOctNovDec2000
2001JanFebMarAprMayJunJulAugSepOctNovDec2001
2002JanFebMarAprMayJunJulAugSepOctNovDec2002
2003JanFebMarAprMayJunJulAugSepOctNovDec2003
2004JanFebMarAprMayJunJulAugSepOctNovDec2004
2005JanFebMarAprMayJunJulAugSepOctNovDec2005
2006JanFebMarAprMayJunJulAugSepOctNovDec2006
2007JanFebMarAprMayJunJulAugSepOctNovDec2007
2008JanFebMarAprMayJunJulAugSepOctNovDec2008
2009JanFebMarAprMayJunJulAugSepOctNovDec2009
2010JanFebMarAprMayJunJulAugSepOctNovDec2010
2011JanFebMarAprMayJunJulAugSepOctNovDec2011
2012JanFebMarAprMayJunJulAugSepOctNovDec2012
2013JanFebMarAprMayJunJulAugSepOctNovDec2013
2014JanFebMarAprMayJunJulAugSepOctNovDec2014
2015JanFebMarAprMayJunJulAugSepOctNovDec2015
2016JanFebMarAprMayJunJulAugSepOctNovDec2016
2017JanFebMarAprMayJunJulAugSepOctNovDec2017
2018JanFebMarAprMayJunJulAugSepOctNovDec2018
2019JanFebMarAprMayJunJulAugSepOctNovDec2019
2020JanFebMarAprMay2020

Authors:A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Custom Search

Messages from 145850

Article: 145850
Subject: Re: How a state machine is constructed using latches?
From: Weng Tianxiang <wtxwtx@gmail.com>
Date: Thu, 25 Feb 2010 17:01:35 -0800 (PST)
Links: << >>  << T >>  << A >>
On Feb 25, 11:34=A0am, Andy <jonesa...@comcast.net> wrote:
> On Feb 25, 5:49=A0am, rickman <gnu...@gmail.com> wrote:
>
> > If the combinatorial logic had been described in the sequential
> > process, there would have been no possibility of generating a latch.
>
> Amen!
>
> Andy

Rick,
Try this one and there is no lock problem any more in VHDL. See what
happens.

  CombProc : process(CombReg, C01, C02)
  begin
    case CombReg is
      when '1' =3D>           <-- only change, and not locked again
        if (C01 =3D '1') then
          Comb <=3D '0';
        elsif (C02 =3D '1') then
          Comb <=3D '1';
        else
          null;
        end if;
      when others =3D>
        Comb <=3D '1';
    end case;
  end process;

Thank you.

Weng

Article: 145851
Subject: Re: using an FPGA to emulate a vintage computer
From: scott@slp53.sl.home (Scott Lurndal)
Date: 26 Feb 2010 01:24:17 GMT
Links: << >>  << T >>  << A >>
"(see below)" <yaldnif.w@blueyonder.co.uk> writes:
>On 25/02/2010 23:26, in article SGDhn.70229$Hk6.39325@news.usenetserver.com,
>"Scott Lurndal" <scott@slp53.sl.home> wrote:
>
>> "(see below)" <yaldnif.w@blueyonder.co.uk> writes:
>>> On 24/02/2010 20:37, in article hm6fbd68gp@news6.newsguy.com, "Michael
>>> Wojcik" <mwojcik@newsguy.com> wrote:
>>> 
>>>> (see below) wrote:
>>>>> 
>>>>> Just the usual red tape: return address, frame pointer of caller; and
>>>>> either
>>>>> a static pointer or some housekeeping for 'display' registers (if used) to
>>>>> access non-locals. But bear in mind that in decent languages arrays are
>>>>> storable values, so a value array parameter gets copied in toto, unlike C.
>>>> 
>>>> It will be in C if the array is wrapped in a struct. Letting array
>>> 
>>> That is passing a struct, not an array.
>>> 
>>>> parameters decay to pointers was a feature of early C that couldn't be
>>>> changed for historical reasons, but when the standardization committee
>>>> added support for struct parameters, they made them first-class.
>>> 
>>>> struct (and not the misnamed "typedef") is C's mechanism for creating
>>>> new types and ADTs, so if you want a pass-by-value array in C, the
>>>> correct thing to do is to put it in a struct.
>>> 
>>> Yes. Preposterous, isn't it?
>> 
>> Q?  Why would anyone want to pass an array by value?
>
>Why would anyone want to wrap an array in a struct and pass that by value?

Why answer a question with another question?

I've never promoted or suggested that one put an array in a struct
and pass it by value, I frankly think it would be a stupid thing to
do in a C program.

I was curious if anyone thought passing an array by value was a
_good_ idea.

scott


Article: 145852
Subject: Re: using an FPGA to emulate a vintage computer
From: glen herrmannsfeldt <gah@ugcs.caltech.edu>
Date: Fri, 26 Feb 2010 02:02:01 +0000 (UTC)
Links: << >>  << T >>  << A >>
In comp.arch.fpga Scott Lurndal <scott@slp53.sl.home> wrote:
(snip, someone wrote)
>>> Q?  Why would anyone want to pass an array by value?

>>Why would anyone want to wrap an array in a struct and pass that by value?
 
> Why answer a question with another question?
 
> I've never promoted or suggested that one put an array in a struct
> and pass it by value, I frankly think it would be a stupid thing to
> do in a C program.

It might make sense for a small array.  You might have an rgb
array dimensioned [3] instead of three separae variables.  
The dimension, I believe, has to be a compile time constant.

-- glen 

Article: 145853
Subject: Re: EDK spi ip core
From: johnp <jprovidenza@yahoo.com>
Date: Thu, 25 Feb 2010 19:46:38 -0800 (PST)
Links: << >>  << T >>  << A >>
On Feb 25, 2:04=A0pm, austin <aus...@xilinx.com> wrote:
> John,
>
> I just love the Dilbert cartoon where they try to out-do each other
> about the 'old days:'
>
> "I used to program in 1's and 0's!"
>
> "That's nothing, all we had were l's and O's ( small letter L and
> capital letter O)"
>
> "Heck, all I had were 0's...."
>
> Yes, I have some 1702's, along with the 4004 4 bit CPU, and some 2102
> SRAM devices Intel handed out to customers to "introduce" them to the
> microcomputer.
>
> I just remember that if you put the 1702 in the socket rotated 180
> degrees, it blew out all the bond wires. =A0Someone came to the lab one
> day saying "did you know that the EPROM lights up when you program
> it?"
>
> Austin

Austin -

I was at a company that create a dual 4004  syetem for reading digital
holograms.  It was quite an
eye opener for me - senior in high school working at a company with a
ton of leading edge technology.

I still have my 4004 programming cheat-sheet.

John

Article: 145854
Subject: Re: using an FPGA to emulate a vintage computer
From: Joe Pfeiffer <pfeiffer@cs.nmsu.edu>
Date: Thu, 25 Feb 2010 21:02:47 -0700
Links: << >>  << T >>  << A >>
glen herrmannsfeldt <gah@ugcs.caltech.edu> writes:

> In comp.arch.fpga Scott Lurndal <scott@slp53.sl.home> wrote:
> (snip, someone wrote)
>>>> Q?  Why would anyone want to pass an array by value?
>
>>>Why would anyone want to wrap an array in a struct and pass that by value?
>  
>> Why answer a question with another question?
>  
>> I've never promoted or suggested that one put an array in a struct
>> and pass it by value, I frankly think it would be a stupid thing to
>> do in a C program.
>
> It might make sense for a small array.  You might have an rgb
> array dimensioned [3] instead of three separae variables.  
> The dimension, I believe, has to be a compile time constant.

It doesn't.  You can use malloc() to allocate an arbitrary-sized buffer,
and then use array syntax to access elements of the buffer.  You can
also pass the address of the buffer, and use it like an array in the
called procedure.

Since C99, you can allocate an array with a variable number of elements
like this:

    printf(" array size >> ");
    scanf("%d", &size);

    int awry[size];
-- 
As we enjoy great advantages from the inventions of others, we should
be glad of an opportunity to serve others by any invention of ours;
and this we should do freely and generously. (Benjamin Franklin)

Article: 145855
Subject: Re: antti alive message
From: Antti <antti.lukats@googlemail.com>
Date: Thu, 25 Feb 2010 21:59:34 -0800 (PST)
Links: << >>  << T >>  << A >>
On Feb 26, 12:02=A0am, -jg <jim.granvi...@gmail.com> wrote:
> On Feb 25, 11:18=A0pm, Antti <antti.luk...@googlemail.com> wrote:
>
> > but the time til embedded is just crazy all things happening at worst t=
ime.. as usual :)
>
> So what's going to be new @ embedded ? ;)
>
> -jg

i will know next week :)
hm ah, from me? not so much actually most projects still in late
development stage :(

antti

Article: 145856
Subject: Frustration with Vendors!
From: rickman <gnuarm@gmail.com>
Date: Thu, 25 Feb 2010 22:43:38 -0800 (PST)
Links: << >>  << T >>  << A >>
Sometimes vendors act like they don't want you to use their parts.  I
am looking for rise/fall time information on an FPGA output in one
voltage mode LVCMOS33 and the various drive and slew rate options.
This doesn't sound like a difficult thing to ask for, but it seems to
be a very difficult thing to get.  I recall the rise/fall times to be
something that is very common in data sheets.  They just pick a set of
conditions and give the data.  Even if that does not match your
circuit design perfectly, it is a data point to start with.

In my case, I am seeing a ridiculously slow rise time with the current
setting which happens to be the lowest current and slowest slew rate.
I guess that is not unexpected.  In fact, I'm a bit surprised we
didn't see a problem with it before now. If I go with the highest
drive and fast slew rate, I get very significant overshoot which is
also not surprising.

So obviously I need to find a happy medium.  I could make up some
boards with different drive settings and see how they work, but there
are 10 combinations total and this is a bit of a PITA and has to
involve my customer to make the measurements.

Since they don't include rise time info in the data sheet, I thought,
maybe I'll contact support and get the info.  That was last Friday
when I called thinking this was such a simple request that maybe they
could answer the question on the phone... silly me.  I have not
received a reply from that contact yet!

Yesterday I got tired of waiting and in addition to pinging support by
email, I made a post in their forum.  That seems to have gotten a
response but not an answer.  I am repeatedly told that the info would
do me no good since it would not match my circuit; I can get this info
from an IBIS simulation and several other ideas of how to get the
info... meanwhile I'm not actually getting the info from support.

I don't have a way to simulate IBIS models.  I tried to convert the
IBIS file to a spice model, but the resulting file was not compatible
with the spice I use.  I was told to manually read the IBIS model, but
it is a huge thing that includes all of the IO modes with such cryptic
names that I have no way of knowing which section is for which IO
setting.  They even have been giving me advice on how to properly
design a transmission line!  The guy has all but written a book of
advice for me on all this, but none of the solutions work for me.  It
just seems absurd that support is going to so much trouble to give me
advice I don't want in lieu of some very simple data I do want.

So I am going to have to build a bit file with each of the various
setting combinations and spend the afternoon measuring each one.  It
just seems like such a waste of time, but it will be easier than
trying to pass the camel of support through the eye of the needle of
my question.

Rick

Article: 145857
Subject: Re: using an FPGA to emulate a vintage computer
From: Charles Richmond <frizzle@tx.rr.com>
Date: Fri, 26 Feb 2010 00:58:50 -0600
Links: << >>  << T >>  << A >>
glen herrmannsfeldt wrote:
> 
>     [snip...]             [snip...]            [snip...]
>  
>> As Al Stewart once sang, "I was jumping to conclusions, and one of them
>> jumped back."
> 

"If you stare into the Abyss long enough,
  the Abyss stares back at you."

     -- Friedrich Nietzsche

-- 
+----------------------------------------+
|     Charles and Francis Richmond       |
|                                        |
|  plano dot net at aquaporin4 dot com   |
+----------------------------------------+

Article: 145858
Subject: Re: using an FPGA to emulate a vintage computer
From: Charles Richmond <frizzle@tx.rr.com>
Date: Fri, 26 Feb 2010 01:09:37 -0600
Links: << >>  << T >>  << A >>
glen herrmannsfeldt wrote:
> In comp.arch.fpga Scott Lurndal <scott@slp53.sl.home> wrote:
> (snip, someone wrote)
>>>> Q?  Why would anyone want to pass an array by value?
> 
>>> Why would anyone want to wrap an array in a struct and pass that by value?
>  
>> Why answer a question with another question?
>  
>> I've never promoted or suggested that one put an array in a struct
>> and pass it by value, I frankly think it would be a stupid thing to
>> do in a C program.
> 
> It might make sense for a small array.  You might have an rgb
> array dimensioned [3] instead of three separae variables.  
> The dimension, I believe, has to be a compile time constant.
> 
> -- glen 

Heck, for RGB, just use a struct with three variables in it.

The dimensions of arrays *used* to have to be compile time 
constants. Now they have a type of array declared in a function 
that can have its size depend on an integer passed into the 
function. (I forget what they call it...  maybe a "dynamic array" 
or something.)

-- 
+----------------------------------------+
|     Charles and Francis Richmond       |
|                                        |
|  plano dot net at aquaporin4 dot com   |
+----------------------------------------+

Article: 145859
Subject: Re: using an FPGA to emulate a vintage computer
From: Charles Richmond <frizzle@tx.rr.com>
Date: Fri, 26 Feb 2010 01:10:42 -0600
Links: << >>  << T >>  << A >>
Joe Pfeiffer wrote:
> glen herrmannsfeldt <gah@ugcs.caltech.edu> writes:
> 
>> In comp.arch.fpga Scott Lurndal <scott@slp53.sl.home> wrote:
>> (snip, someone wrote)
>>>>> Q?  Why would anyone want to pass an array by value?
>>>> Why would anyone want to wrap an array in a struct and pass that by value?
>>  
>>> Why answer a question with another question?
>>  
>>> I've never promoted or suggested that one put an array in a struct
>>> and pass it by value, I frankly think it would be a stupid thing to
>>> do in a C program.
>> It might make sense for a small array.  You might have an rgb
>> array dimensioned [3] instead of three separae variables.  
>> The dimension, I believe, has to be a compile time constant.
> 
> It doesn't.  You can use malloc() to allocate an arbitrary-sized buffer,
> and then use array syntax to access elements of the buffer.  You can
> also pass the address of the buffer, and use it like an array in the
> called procedure.
> 
> Since C99, you can allocate an array with a variable number of elements
> like this:
> 
>     printf(" array size >> ");
>     scanf("%d", &size);
> 
>     int awry[size];

But how about the second dimension, Joe??? Can you allocate:

       int awry2[size][size];

-- 
+----------------------------------------+
|     Charles and Francis Richmond       |
|                                        |
|  plano dot net at aquaporin4 dot com   |
+----------------------------------------+

Article: 145860
Subject: Re: FPGA platform??
From: Thomas Stanka <usenet_nospam_valid@stanka-web.de>
Date: Thu, 25 Feb 2010 23:38:59 -0800 (PST)
Links: << >>  << T >>  << A >>
On 25 Feb., 11:21, Petter Gustad <newsmailco...@gustad.com> wrote:
> On the other hand the Synopsys VCS simulator is not available for
> Windows.

Last time I used Synopsys Simulator is 10 years ago, but I don't
missed it since then :).

> > Several parts of the design suites ISPLever are Windows only,
> > Programming Actel FPGAs is only possible using Windows...
>
> Does that mean you can't generate a SVF file either?

You can generate a programming file under linux. But you can't use the
programmer (and programmer SW) neither for Antifuse nor for Flash-
based.
The core generator for more complex cores(PCI and so on) also requires
Windows.
And as already stated, the actual version of designer under Linux is
to slow to do reasonable layout/floorplan of complex designs.


bye Thomas



Article: 145861
Subject: Re: using an FPGA to emulate a vintage computer
From: glen herrmannsfeldt <gah@ugcs.caltech.edu>
Date: Fri, 26 Feb 2010 08:34:07 +0000 (UTC)
Links: << >>  << T >>  << A >>
In comp.arch.fpga Charles Richmond <frizzle@tx.rr.com> wrote:
(snip)
 
> Heck, for RGB, just use a struct with three variables in it.

Well, the suggestion was an array in a struct.  With an array
you can loop over it.
 
> The dimensions of arrays *used* to have to be compile time 
> constants. Now they have a type of array declared in a function 
> that can have its size depend on an integer passed into the 
> function. (I forget what they call it...  maybe a "dynamic array" 
> or something.)

Yes, but can you do that for an array in a struct.  If you 
pass it in a function call, and it isn't the last argument, how
will the called routine know where the other arguments are?

I haven't done much with C99 yet.

-- glen
 

Article: 145862
Subject: Re: FPGA platform??
From: Petter Gustad <newsmailcomp6@gustad.com>
Date: Fri, 26 Feb 2010 10:25:06 +0100
Links: << >>  << T >>  << A >>
Thomas Stanka <usenet_nospam_valid@stanka-web.de> writes:

> Last time I used Synopsys Simulator is 10 years ago, but I don't
> missed it since then :).

I've used VCS since it was first released by Chronologic until two
years ago, since then I've used ModelSim and I really miss VCS...

>> > Several parts of the design suites ISPLever are Windows only,
>> > Programming Actel FPGAs is only possible using Windows...
>>
>> Does that mean you can't generate a SVF file either?
>
> You can generate a programming file under linux. But you can't use the
> programmer (and programmer SW) neither for Antifuse nor for Flash-
> based.
> The core generator for more complex cores(PCI and so on) also requires
> Windows.
> And as already stated, the actual version of designer under Linux is
> to slow to do reasonable layout/floorplan of complex designs.

It's probably a tough job for the smaller companies to develop
multi-platform software since they don't have the resources that
Xilinx and Altera has. 

However, it could have been interesting if some of the smaller vendors
would open source their software to get some community help. But some
of their software might be based upon some commercial packages outside
their control, which makes it impossible unless it's re-written.

Petter
-- 
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

Article: 145863
Subject: Re: Altera data sheets.
From: David Brown <david@westcontrol.removethisbit.com>
Date: Fri, 26 Feb 2010 10:43:57 +0100
Links: << >>  << T >>  << A >>
On 25/02/2010 13:56, rickman wrote:
> On Feb 25, 6:04 am, Symon<symon_bre...@hotmail.com>  wrote:
>> If anyone from Altera reads this forum, can they please email/call their
>> manual writing&  publishing department and complain from me that their
>> stupid PDF manuals have occasional pages turned at 90 degrees, e.g. the
>> Stratix4 Handbook, page 1-11. This is very annoying, as it means my
>> reader displays all the other pages narrower than they would be. I'm
>> getting on a bit now, my eyesight isn't what it was, and I'm too
>> cantankerous to piss about with the magnifying glass tool. I'm perfectly
>> capable of using the special rotate button that the reader provides for
>> the odd occasion when the page needs to be turned, in the same way I
>> used to be able to turn a book in the good old days. Those dumbasses
>> (probably) wouldn't print a book with occasional pages sticking out, why
>> do they feel the need to do it with their PDF manuals.
>>
>> The stupid thing is, doing what they have done, doesn't make the table
>> any easier to read on a computer screen than if they'd made the table
>> smaller and printed it across the page. It just makes all the other
>> pages harder to read. The only time it helps is if some bozo decides
>> he's gonna print out 27MB of file, in which case they're probably a
>> student and have good eyesight anyway.
>>
>> This is the only reason stopping me from designing in Altera parts.
>> Xilinx have nice PDF files.
>>
>> Love, Syms.
>>
>> p.s. There's no charge for this free advice.
>
> Maybe you should instead complain to Adobe about their *stupid* PDF
> reading software.  The only reason that the rotated pages are making
> the others hard to view is because you are using "fit to page width"
> for a magnification.  In lieu of getting either of these multi-

I can't see this effect with any pdf reader I've tried - Foxit which I 
normally use on Windows, evince on Ubuntu, or Acrobat Reader 8 on 
Windows.  Maybe you are using an old version of Acrobat Reader?

It makes sense to complain to Adobe about how they have managed to make 
such an insecure file reader, or to ask why they have allowed executable 
javascript and plugins by default, or why their software is orders of 
magnitude bigger, slower, and more ram-hungry than alternatives such as 
Foxit.  But I am totally failing to replicate these viewing problems.

> national corporations to change the way they do business, perhaps you
> could do a very little leg work yourself.  One is to just view them
> with a set magnification which will show all pages at the same zoom
> level.  It's not really so hard to do.  You just type in a zoom level
> that lets you view the first page to fit the width of the window.
>
> The other method can only be done if Altera has not write or read
> protected their data sheets.  You can use a PDF editing tool to
> actually rotate the page in the document and then save it so it will
> be forever fixed.  If you find that Altera's data sheets are write
> protected, then you are screwed.  I have seen some data sheets that
> are *read* protected, or more accurately, copy protected.  Yes, they
> prevent you from using select, copy and paste to pull any information
> out of the document.  I find that insane and it drives me pretty much
> up a wall.  If I want to quote something from a data sheet, such as a
> part number for ordering, I want to *COPY* it so as to eliminate the
> possibility of a transcription error.  With part number containing
> some 12 or more digits and letters, it is oh so easy to mess it up.
> Even more interesting is when I find a document that is protected in
> some way, but they forgot to password protect it, so I can turn off
> the protection...  But I think you can use some third party tools to
> get around the password protection.  After all, if you can read the
> document so that it can be viewed, you can always copy and/or edit
> it.  The "protection" is just a switch in the program you are reading
> it with.
>

Rather than going through all this effort, install a decent (free and 
open-source) pdf printer such as PDFCreator.  Then you can "print" your 
document to a new pdf file that has all the pages at the same 
orientation, and is certainly editable if you want.

> BTW, you can blame all of this on the community standardizing on a
> proprietary document format instead of open source.  There seem to be
> open source tools for PDF files now, but it has taken a long time and
> most people don't know about them.
>

PDF came from a proprietary source, but it is an ISO standard (at least, 
for some version of pdf format) now.  The format has been well known 
since it became popular, and there have been open source tools for PDF 
reading, generation, and editing for years - the xpdf viewer is at least 
14 years old, and pdfLatex for generating pdf files is at least 12 years 
old.  While the pdf standard could be more "open", it is pretty good as 
standards go.



Article: 145864
Subject: Re: Frustration with Vendors!
From: Uwe Bonnes <bon@elektron.ikp.physik.tu-darmstadt.de>
Date: Fri, 26 Feb 2010 09:52:53 +0000 (UTC)
Links: << >>  << T >>  << A >>
rickman <gnuarm@gmail.com> wrote:
> Sometimes vendors act like they don't want you to use their parts.  I
> am looking for rise/fall time information on an FPGA output in one
> voltage mode LVCMOS33 and the various drive and slew rate options.
> This doesn't sound like a difficult thing to ask for, but it seems to
> be a very difficult thing to get.  I recall the rise/fall times to be
> something that is very common in data sheets.  They just pick a set of
> conditions and give the data.  Even if that does not match your
> circuit design perfectly, it is a data point to start with.

> In my case, I am seeing a ridiculously slow rise time with the current
> setting which happens to be the lowest current and slowest slew rate.
> I guess that is not unexpected.  In fact, I'm a bit surprised we
> didn't see a problem with it before now. If I go with the highest
> drive and fast slew rate, I get very significant overshoot which is
> also not surprising.

Go back to the basic, starting without transmission line effects.
With 10 mA source current and 10 pf load, dU/dt = 10 mA/10pF = 1V/nS

10 pF is probably no bad guestimate for one output with one pin load and
some trace... 

So probably series termination is another approach you should consider.

Bye
-- 
Uwe Bonnes                bon@elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------

Article: 145865
Subject: Re: Altera data sheets.
From: David Brown <david@westcontrol.removethisbit.com>
Date: Fri, 26 Feb 2010 11:19:55 +0100
Links: << >>  << T >>  << A >>
On 25/02/2010 15:43, Symon wrote:
> On 2/25/2010 12:56 PM, rickman wrote:
>>
>> The other method can only be done if Altera has not write or read
>> protected their data sheets. You can use a PDF editing tool to
>> actually rotate the page in the document and then save it so it will
>> be forever fixed.
>
> Actually, that provoked me. You need Acrobat professional. Which isn't
> free.
>

Since you already use Foxit for reading, you should probably look at 
Foxit Editor rather than Acrobat Writer.  I've not used it myself, but 
considering how much better Foxit reader is than Acrobat reader, I'd 
look there first.

pdfedit is an alternative for Linux, but it's a bit slow, and it Foxit 
has trouble reading the files it produces (apparently it's a bug in 
Foxit, not pdfedit).


>
> File-> Create PDF -> from file
>
> Document -> Rotate Pages ->
> Counterclockwise 90 degrees
> Landscape pages
>
> Lovely. Maybe I will use their parts after all. It's still dumb the way
> they publish the PDFs.
>
> Syms.


Article: 145866
Subject: Re: Altera data sheets.
From: Symon <symon_brewer@hotmail.com>
Date: Fri, 26 Feb 2010 10:38:33 +0000
Links: << >>  << T >>  << A >>
On 2/26/2010 9:43 AM, David Brown wrote:

> Foxit. But I am totally failing to replicate these viewing problems.
>

Hi David,

I don't like to see failure.

I have Foxit 3.1.4.1125, which seems quite up-to-date.

I have set the default to show the pages at their biggest, i.e. 'fit 
width', because I am getting old and my eyes aren't like they used to 
be. When I load :-

http://www.altera.com/literature/hb/stratix-iv/stx4_siv51001.pdf

The portrait pages in it, e.g. pg 1-1, no longer 'fit width', because 
there are pages like 1-11 that, and this is my complaint, are included 
in landscape mode. The reader's rotate button doesn't help, 'cos it 
rotates every page. The solution is to publish documents with all pages 
portrait and draw the tables across the page.

This is 'totally' driving me bonkers, and is why I keep clogging up the 
useful discourse on CAF with these ridiculous posts.

If you don't see this effect, please, for God's sake, put me out of my 
misery, and let me know what you did.

Thanks, Syms.

p.s. A similar thing happens in my old version 7 Adobe viewer, but only 
after the viewer has 'seen' a landscape page.

Article: 145867
Subject: Re: Frustration with Vendors!
From: rickman <gnuarm@gmail.com>
Date: Fri, 26 Feb 2010 02:39:24 -0800 (PST)
Links: << >>  << T >>  << A >>
On Feb 26, 4:52=A0am, Uwe Bonnes <b...@elektron.ikp.physik.tu-
darmstadt.de> wrote:
> rickman <gnu...@gmail.com> wrote:
> > Sometimes vendors act like they don't want you to use their parts. =A0I
> > am looking for rise/fall time information on an FPGA output in one
> > voltage mode LVCMOS33 and the various drive and slew rate options.
> > This doesn't sound like a difficult thing to ask for, but it seems to
> > be a very difficult thing to get. =A0I recall the rise/fall times to be
> > something that is very common in data sheets. =A0They just pick a set o=
f
> > conditions and give the data. =A0Even if that does not match your
> > circuit design perfectly, it is a data point to start with.
> > In my case, I am seeing a ridiculously slow rise time with the current
> > setting which happens to be the lowest current and slowest slew rate.
> > I guess that is not unexpected. =A0In fact, I'm a bit surprised we
> > didn't see a problem with it before now. If I go with the highest
> > drive and fast slew rate, I get very significant overshoot which is
> > also not surprising.
>
> Go back to the basic, starting without transmission line effects.
> With 10 mA source current and 10 pf load, dU/dt =3D 10 mA/10pF =3D 1V/nS
>
> 10 pF is probably no bad guestimate for one output with one pin load and
> some trace...
>
> So probably series termination is another approach you should consider.

Where did you get any of the data you are talking about?  How did you
come up with 10 mA?

I could have done all sorts of things if I want to make assumptions,
but they would be just that, assumptions and not information.  The
settings include current drive of 4, 8, 12, 16 and 20 mA along with
speed settings of FAST and SLOW.  Clearly you can't just do a
calculation based on the rated current since that would leave no room
for the FAST/SLOW setting.  I believe I was told by one of the FPGA
vendors that their parts had current controlled internal nodes which
could set the slew rate.  So it may be that the speed setting alone
controls the slew rate of a bare pin.  Like I said, that would be a
good start, but until I can get an informative reply I am left only
with building 10 different bit files, loading up 10 different boards
and taking 10 measurements.  Not my idea of a fun afternoon.

Rick

Article: 145868
Subject: Re: Altera data sheets.
From: rickman <gnuarm@gmail.com>
Date: Fri, 26 Feb 2010 02:44:56 -0800 (PST)
Links: << >>  << T >>  << A >>
On Feb 26, 5:38=A0am, Symon <symon_bre...@hotmail.com> wrote:
> On 2/26/2010 9:43 AM, David Brown wrote:
>
> > Foxit. But I am totally failing to replicate these viewing problems.
>
> Hi David,
>
> I don't like to see failure.
>
> I have Foxit 3.1.4.1125, which seems quite up-to-date.
>
> I have set the default to show the pages at their biggest, i.e. 'fit
> width', because I am getting old and my eyes aren't like they used to
> be. When I load :-
>
> http://www.altera.com/literature/hb/stratix-iv/stx4_siv51001.pdf
>
> The portrait pages in it, e.g. pg 1-1, no longer 'fit width', because
> there are pages like 1-11 that, and this is my complaint, are included
> in landscape mode. The reader's rotate button doesn't help, 'cos it
> rotates every page. The solution is to publish documents with all pages
> portrait and draw the tables across the page.
>
> This is 'totally' driving me bonkers, and is why I keep clogging up the
> useful discourse on CAF with these ridiculous posts.
>
> If you don't see this effect, please, for God's sake, put me out of my
> misery, and let me know what you did.
>
> Thanks, Syms.
>
> p.s. A similar thing happens in my old version 7 Adobe viewer, but only
> after the viewer has 'seen' a landscape page.

I've seen this before in Acrobat and it shows up when the document is
opened.  There are settings that control the initial view and I didn't
explore how they were set, but it was due to a page being landscape
controlling the default magnification of the entire document.

Like I said before, I have my own nits to pick with data sheets and it
really does make a difference about what parts I consider.  Heck,
there is an inductor company that puts everything on web pages and not
even all on one page!  You have to visit multiple pages to get all the
data on their parts.  Maybe they have updated by now, but have I never
used any of their parts because it was such a PITA to store the data
sheet.

Rick

Article: 145869
Subject: Re: Frustration with Vendors!
From: "Nial Stewart" <nial*REMOVE_THIS*@nialstewartdevelopments.co.uk>
Date: Fri, 26 Feb 2010 11:30:18 -0000
Links: << >>  << T >>  << A >>
>  The
> settings include current drive of 4, 8, 12, 16 and 20 mA along with
> speed settings of FAST and SLOW.  Clearly you can't just do a
> calculation based on the rated current since that would leave no room
> for the FAST/SLOW setting.

I might be wrong, but I _think_ that in Quartus a FAST or SLOW assignment
overrides the current setting, so that's fewer variations to worry about.

> I am left only
> with building 10 different bit files, loading up 10 different boards
> and taking 10 measurements.  Not my idea of a fun afternoon.


Sure it wouldn't take too long to knock up a mickey mouse design that
just toggles a single pin then vary the assignments. You could have a new
test re-built and programmed in a minute or two.

Or are there other constraints?



Nial. 



Article: 145870
Subject: Re: using an FPGA to emulate a vintage computer
From: Ahem A Rivet's Shot <steveo@eircom.net>
Date: Fri, 26 Feb 2010 11:56:22 +0000
Links: << >>  << T >>  << A >>
On Wed, 24 Feb 2010 11:31:45 -0800 (PST)
Eric Chomko <pne.chomko@comcast.net> wrote:

> On Feb 23, 2:07 pm, "(see below)" <yaldni...@blueyonder.co.uk> wrote:
> > On 23/02/2010 17:52, in article
> > 3ec03225-3a0f-4bcd-9db1-51201d1b3...@w12g2000vbj.googlegroups.com, "Eric
> >
> > Chomko" <pne.cho...@comcast.net> wrote:
> > > But an ALGOL "activation record" (stack frame) had a lot more than
> > > that. As I recall, they copied a lot more just pointers and parameter
> > > values.
> >
> > Just the usual red tape: return address, frame pointer of caller; and
> > either a static pointer or some housekeeping for 'display' registers
> > (if used) to access non-locals. But bear in mind that in decent
> > languages arrays are storable values, so a value array parameter gets
> > copied in toto, unlike C.
> >
> 
> Are you saying that C doesn't implement true recursion? I have only

	No, he's saying that C doesn't really implement an array type, the
var[offset] syntax is just syntactic sugar for *(var + offset) which is why
things like 3[x] work the same as x[3] in C.

-- 
Steve O'Hara-Smith                          |   Directable Mirror Arrays
C:>WIN                                      | A better way to focus the sun
The computer obeys and wins.                |    licences available see
You lose and Bill collects.                 |    http://www.sohara.org/

Article: 145871
Subject: Re: Frustration with Vendors!
From: Symon <symon_brewer@hotmail.com>
Date: Fri, 26 Feb 2010 12:43:45 +0000
Links: << >>  << T >>  << A >>
If I was gonna guess how FPGA's outputs with programmable drive and slew 
work, I'd say there are a bunch of FETs in parallel, turning on more of 
them for more drive. So, for 2mA, just one FET gets turned on, for 24mA, 
all of them do. The gate current to these FETs can be limited, which 
gives slower skew, or not limited which means they go as fast as possible.

It would be impossible for a vendor to publish a 'rise time' for these 
devices, because of the many different settings, which is why the IBIS 
files are great.

Cheers, Syms.

Article: 145872
Subject: Re: Altera data sheets.
From: David Brown <david@westcontrol.removethisbit.com>
Date: Fri, 26 Feb 2010 13:58:57 +0100
Links: << >>  << T >>  << A >>
On 26/02/2010 11:38, Symon wrote:
> On 2/26/2010 9:43 AM, David Brown wrote:
>
>> Foxit. But I am totally failing to replicate these viewing problems.
>>
>
> Hi David,
>
> I don't like to see failure.
>
> I have Foxit 3.1.4.1125, which seems quite up-to-date.
>

That's what I am using too.

> I have set the default to show the pages at their biggest, i.e. 'fit
> width', because I am getting old and my eyes aren't like they used to
> be. When I load :-
>
> http://www.altera.com/literature/hb/stratix-iv/stx4_siv51001.pdf
>
> The portrait pages in it, e.g. pg 1-1, no longer 'fit width', because
> there are pages like 1-11 that, and this is my complaint, are included
> in landscape mode. The reader's rotate button doesn't help, 'cos it
> rotates every page. The solution is to publish documents with all pages
> portrait and draw the tables across the page.
>
> This is 'totally' driving me bonkers, and is why I keep clogging up the
> useful discourse on CAF with these ridiculous posts.
>

It may be off-topic for this newsgroup, but I have certainly learned 
enough from your posts over the years to be happy to try to help - if I can.

> If you don't see this effect, please, for God's sake, put me out of my
> misery, and let me know what you did.
>

I've figured it out - you are using "continuous" mode, so that the pdf 
reader is looking at the document as though it were one very tall page, 
and thus fit-width applies to the this whole continuous page.  I prefer 
"single page" mode, in which fit-width (and fit-page) apply to a single 
page at a time.

Hope that helps,

David.


> Thanks, Syms.
>
> p.s. A similar thing happens in my old version 7 Adobe viewer, but only
> after the viewer has 'seen' a landscape page.


Article: 145873
Subject: Re: Altera data sheets.
From: Symon <symon_brewer@hotmail.com>
Date: Fri, 26 Feb 2010 13:57:29 +0000
Links: << >>  << T >>  << A >>
On 2/26/2010 12:58 PM, David Brown wrote:
>
> I've figured it out - you are using "continuous" mode, so that the pdf
> reader is looking at the document as though it were one very tall page,
> and thus fit-width applies to the this whole continuous page. I prefer
> "single page" mode, in which fit-width (and fit-page) apply to a single
> page at a time.
>
> Hope that helps,
>
> David.

David, you've solved it! I tried going into single page mode before, but 
I didn't re-click the fit-width thing.
Cheers!

p.s. I still maintain Altera are wrong to have landscape pages mixed in! 
I like continuous mode.

Article: 145874
Subject: Re: Frustration with Vendors!
From: rickman <gnuarm@gmail.com>
Date: Fri, 26 Feb 2010 07:28:36 -0800 (PST)
Links: << >>  << T >>  << A >>
On Feb 26, 7:43=A0am, Symon <symon_bre...@hotmail.com> wrote:
> It would be impossible for a vendor to publish a 'rise time' for these
> devices, because of the many different settings, which is why the IBIS
> files are great.

Why would it be "impossible" to publish rise time data for parts?
They publish delay information for all the various parts with
modifiers for the IO standards.  Heck, I bet the rise time data is
easier since it is likely the same across speed grades and parts.  It
may vary with package, so it is a wash.

The IBIS files are only great if you have a way of simulating them.
Oh, the vendors could also provide the *SAME* data in a spice file,
not the high accuracy, design detail revealing spice models that they
consider proprietary, but models derived from the IBIS descriptions
which reveal nothing about your parts the IBIS files don't.

I think this is one of those areas where vendors just don't listen
well enough to their customers to meet their needs.  They see spice
models as "bad" because they don't want their IO "secrets" revealed
and don't get that a spice model is so much better for the users than
IBIS models.  Or better yet, go ahead and provide some basic data when
requested.  Jeeze, these guys actually suggested for me to pull the
data from the 80 kB IBIS file with all its cryptic notation and put it
in a spread sheet!!!

Rick



Site Home   Archive Home   FAQ Home   How to search the Archive   How to Navigate the Archive   
Compare FPGA features and resources   

Threads starting:
1994JulAugSepOctNovDec1994
1995JanFebMarAprMayJunJulAugSepOctNovDec1995
1996JanFebMarAprMayJunJulAugSepOctNovDec1996
1997JanFebMarAprMayJunJulAugSepOctNovDec1997
1998JanFebMarAprMayJunJulAugSepOctNovDec1998
1999JanFebMarAprMayJunJulAugSepOctNovDec1999
2000JanFebMarAprMayJunJulAugSepOctNovDec2000
2001JanFebMarAprMayJunJulAugSepOctNovDec2001
2002JanFebMarAprMayJunJulAugSepOctNovDec2002
2003JanFebMarAprMayJunJulAugSepOctNovDec2003
2004JanFebMarAprMayJunJulAugSepOctNovDec2004
2005JanFebMarAprMayJunJulAugSepOctNovDec2005
2006JanFebMarAprMayJunJulAugSepOctNovDec2006
2007JanFebMarAprMayJunJulAugSepOctNovDec2007
2008JanFebMarAprMayJunJulAugSepOctNovDec2008
2009JanFebMarAprMayJunJulAugSepOctNovDec2009
2010JanFebMarAprMayJunJulAugSepOctNovDec2010
2011JanFebMarAprMayJunJulAugSepOctNovDec2011
2012JanFebMarAprMayJunJulAugSepOctNovDec2012
2013JanFebMarAprMayJunJulAugSepOctNovDec2013
2014JanFebMarAprMayJunJulAugSepOctNovDec2014
2015JanFebMarAprMayJunJulAugSepOctNovDec2015
2016JanFebMarAprMayJunJulAugSepOctNovDec2016
2017JanFebMarAprMayJunJulAugSepOctNovDec2017
2018JanFebMarAprMayJunJulAugSepOctNovDec2018
2019JanFebMarAprMayJunJulAugSepOctNovDec2019
2020JanFebMarAprMay2020

Authors:A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Custom Search