PSoC or FPGA?

On Sun, 20 Mar 2011 22:45:45 GMT, nico@puntnl.niks (Nico Coesel)
wrote:
...
>You can simulate a lot but creating a set of tests which covers all
>the possible mayhem coming from the outside world is next to
>impossible.

This suggests that making an ASIC work right the first time is next to
impossible but experience shows that it's not. So it's just a matter
of how diligent one is with one's tests.
If you are not simulating, you are leaving a lot on the table with
respect to time (a largish FPGA can take hours to synthesize+p&r),
observability and controllability of the chip under test.
-- 
Muzaffer Kal

DSPIA INC.
ASIC/FPGA Design Services

http://www.dspia.com

On a sunny day (Sun, 20 Mar 2011 15:16:14 -0500) it happened
"krw@att.bizzzzzzzzzzzz" <krw@att.bizzzzzzzzzzzz> wrote in
<62oco610kr2ullbgc3al8rcc0iq1gek6r0@4ax.com>:

>On Sun, 20 Mar 2011 18:14:25 GMT, Jan Panteltje <pNaonStpealmtje@yahoo.com>
>wrote:
>
>
>>
>>There is too much simulations in this world.
>
>You needn't say anything else.  At least you're consistent; clueless.

Take your intelligence for example.

I do not think we will ever see any code from you,
all you do is boast about how big the things are you make,
insult people, etc,
while from the time it takes you to do the simplest things I guess you are at least incompetent, and at most a windbag.

Muzaffer Kal <kal@dspia.com> wrote:

>On Sun, 20 Mar 2011 22:45:45 GMT, nico@puntnl.niks (Nico Coesel)
>wrote:
>...
>>You can simulate a lot but creating a set of tests which covers all
>>the possible mayhem coming from the outside world is next to
>>impossible.
>
>This suggests that making an ASIC work right the first time is next to
>impossible but experience shows that it's not. So it's just a matter
>of how diligent one is with one's tests.

Well, tell that to the big semi manufacturers :-) Many
microcontrollers and SoCs have several versions with bugs. Recently
even Intel got bitten badly.

And there still may be unexpected behaviour coming from the outside
which might not be addressed by the design (incomplete specification).
If you have an ASIC you most probably need to fix the outside world,
if you are using an FPGA (or something else which is programmable) you
most likely end up fixing the FPGA design.

I think FPGA simulation is very usefull but I always got by without it
or used other methods for verification. The maximum size of the
designs I worked on is about 800k to 1M equivalent gates.

-- 
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------

"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message 
news:im5g4j$t06$2@news.albasani.net...
> Just for fun I did a frequency counter, a LCD display driver, and a smart 
> card reader
> all without simulation on a Spartan 2.
> No problem.
> I used iverilog to test some crypto, and then used simulation to test it 
> further.
> I did the TV up converter (15625 to VGA) without simulation, and the sync 
> separator / slicer too.
> and the video filter.
> But I do not use MPlab for PICs either... just write the asm directly.
> Faster and better that way.
>
> There is too much simulations in this world.

There's also too little simulation in the world.

The project you described, yeah, they're well within the realm of being 
straightforward enough to not bother with any simulation before you just 
program up a part and see what happens.  But when you get to more complex 
systems, even with good designers it rapidly becomes obvious that simulation 
more than pays for itself.  E.g., some years back I designed a DMA-based 
memory controller for 8 slots worth of SDRAM SIMMs, and since I wanted it to 
be reasonably efficient the memory controller could have several memory 
accesses in process simulation and would also re-order incoming DMA requests 
to better utilize SDRAM banks that had already been opened for other 
operations.  I'm quite certain that without the Microon-provided SDRAM 
simulation models I used, I would have spent hundreds of additional hours 
trying to get the thing working -- if only due to ending up writing my own 
testbenches, since this had a 128-bit wide data bus running at over 100MHz, 
and I sure didn't have a logic analyzer or anything else that had nearly 
enough inputs to try to watch what was going on -- much less make much sense 
of it all (since all the acceses were so heavily interleaved).

The reason there's too little simulation in the world is that even of people 
who buy into the idea that simulation is a Good Thing, I've seen far too much 
cases where the designer (and this applies to those using C/C++ as well as 
VHDL/Verilog) writes a testbench that only exercises what the design *should* 
do... which is largely worthless; by far the greatest value from testbenches 
comes when you purposely try to destroy your design by feeding it an 
unrelenting stream of garbage data... or at least a stream designed to abuse 
the underlying model as much as possible. :-)   (This is how I tested the 
SDRAM controller -- feeding it a new randomized request through every single 
DMA port on every single clock cycle...)

Although one doesn't always have a choice, it's best if someone else writes 
the testbench for your design... and that that person's deepest desire is to 
make your design fail. :-)

> Reality always rules, use a scope.

For a board level design, sure.  For FPGA and (particularly) IC designs, it's 
quite expensive.

---Joel

John - KD5YI <sophi.2@invalid.org> wrote:

>On 3/20/2011 4:10 AM, fasf wrote:
>> Hi,
>> i've worked wit 8bit/32bit microcontrollers for 5 years and now i want
>> to explore new fields, so i'm interested in these two solutions: PSoC
>> and FPGA. I'm totally new (i don't know neither VHDL nor Verilog) and
>> i don't understand the differences between these programmable devices.
>> For hobby, what do you think is more useful to study? Can you suggest
>> a low cost DevKit?
>> Any getting started suggestion will be very appreciated
>
>
>Well, I will put in a plug for Cypress' PSoC. I've been using them for 
>years. However, if you need blazing speed, you will need to go the FPGA 
>route as the PSoC is nothing more than a microcontroller that has some 
>analog goodies.
>
>I like the PSoC because it is extremely configurable/reconfigurable to 
>almost anything you need. An example that Cypress came out with was a 
>
>I have no financial connection with Cypress. I've just been using their 
>PSoC chips since about 2002.

Looks interesting. I checked the website a bit but couldn't find all I
want to know: How is the analog performance regarding noise and
bandwidth? Can you also use a Psoc as a reconfigurable analog brick
(analog in - analog out)?

-- 
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------

On a sunny day (Mon, 21 Mar 2011 09:58:00 -0700) it happened "Joel Koltner"
<zapwireDASHgroups@yahoo.com> wrote in
<tsLhp.777261$pX3.456772@en-nntp-11.dc1.easynews.com>:

>> There is too much simulations in this world.
>
>There's also too little simulation in the world.

<snip good reasons given>

>> Reality always rules, use a scope.
>
>For a board level design, sure.  For FPGA and (particularly) IC designs, it's 
>quite expensive.

Yes OK, and I use LTspice too...
But what I do not like is where simulations replace what should be reality,
like NASA having simulations of people landing on mars,
while all they can really do is fly around the block (earth).
The brain is quite powerful, and it can do most of the simulations that
supercomputers are now used for, those are merely executing some equations
that are always a subset of reality, then tinkered in a way so they see what they want to see,
and that then is called a new 'theory'.
Or in electronics 'design'.
Simulations is a drug.
What you need is overview, and detailed knowledge of what you are doing.
Bottom up, modular.
Then nothing is impossible, and the sky the limit.
Top-down with simulations sucks.

"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message 
news:im8c6e$crk$1@news.albasani.net...
> Simulations is a drug.
> What you need is overview, and detailed knowledge of what you are doing.
> Bottom up, modular.
> Then nothing is impossible, and the sky the limit.
> Top-down with simulations sucks.

Ever hard this quote, Jan?

--> "Some people, when confronted with a problem, think "I know, I'll use 
regular expressions." Now they have two problems."

:-)

Hi,

I need to connect a 12 volts DC lead acid battery to a circuit. The
circuit draws 100mA and works at 3.3V. I am planning to use 7805 to
drop the voltage from 12 to 5 volts.

The first thing is that how can I bypass the 7805 while charging the
battery?

 The thing is that I also needs to recharge the battery too. The
Circuit and the battery charger both have same input power connector
on them and the battery has the mating connector for both of them.



Thanks
John,

Jan Panteltje wrote:
> On a sunny day (Mon, 21 Mar 2011 09:58:00 -0700) it happened "Joel Koltner"
> <zapwireDASHgroups@yahoo.com>  wrote in
> <tsLhp.777261$pX3.456772@en-nntp-11.dc1.easynews.com>:
>
>>> There is too much simulations in this world.
>>
>> There's also too little simulation in the world.
>
> <snip good reasons given>
>
>>> Reality always rules, use a scope.
>>
>> For a board level design, sure.  For FPGA and (particularly) IC designs, it's
>> quite expensive.
>
> Yes OK, and I use LTspice too...
> But what I do not like is where simulations replace what should be reality,
> like NASA having simulations of people landing on mars,
> while all they can really do is fly around the block (earth).
> The brain is quite powerful, and it can do most of the simulations that
> supercomputers are now used for, those are merely executing some equations
> that are always a subset of reality, then tinkered in a way so they see what they want to see,
> and that then is called a new 'theory'.
> Or in electronics 'design'.
> Simulations is a drug.
> What you need is overview, and detailed knowledge of what you are doing.
> Bottom up, modular.
> Then nothing is impossible, and the sky the limit.
> Top-down with simulations sucks.
>

Taking a simulation and poking it until it sort-of works is a recipe for 
mediocre performance, at best.  On the other hand, board turns and the 
attendant delays are expensive.  In analogue, it's best to design stuff 
by hand and simulate to verify (and maybe optimize some badly-behaved 
stuff that's hard to do by algebra, e.g. parametric effects).

I'm a big fan of debuggers for code, because that makes it faster to 
explore all the branches and reduces the number of bugs that make it 
into the version control system.  I've never done an FPGA, but I suspect 
they might be similar in that respect.

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058

email: hobbs (atsign) electrooptical (period) net
http://electrooptical.net

john1987 wrote:
> Hi,
>
> I need to connect a 12 volts DC lead acid battery to a circuit. The
> circuit draws 100mA and works at 3.3V. I am planning to use 7805 to
> drop the voltage from 12 to 5 volts.
>
> The first thing is that how can I bypass the 7805 while charging the
> battery?
>
>   The thing is that I also needs to recharge the battery too. The
> Circuit and the battery charger both have same input power connector
> on them and the battery has the mating connector for both of them.
>
>
>
> Thanks
> John,

Um, how about putting another connector on the input side of the 7805?

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058

email: hobbs (atsign) electrooptical (period) net
http://electrooptical.net