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Orchid XP v8 wrote:
> Heh. Chris Cason. Is there anything he can't do? ;-)
Get betas out on time?
> I've been to the Xilinx website and looked at the various "development
> boards" they offer, and most of them seem to be around $2,000. Obviously
> I don't have that kind of money. I'll have to hunt around further to see
> if they offer anything at more sane prices.
Hmmm, thought they had some cheap ones. Check out Altera. I seem to recall
they have some small, cheapish (around the $100-$200 mark) boards.
Also, keep an eye out for a CPLD devkit. CPLD's are (simply put) FPGA's
with persistent configuration; i.e. you don't need to re-program them each
time they are powered up.
> Also, if memory serves me correctly, the Xilinx software is a free
> download; they make their money from selling you the hardware. Maybe I
Like Altera they probably have an advanced version of the software that
costs $$$. Back about ten years ago, even the base software version cost
$1000 or so, but then they woke up to the fact that they are a hardware
company and would probably sell more FPGA's if they didn't put barriers in
the way of people designing with them. (This may seem obvious, but to bean
counters, it apparently isn't: e.g. take the fact that Microsoft used to
charge a few grand for the Windows 1.0 and 2.0 SDK's before realising
they'd have more users if it was free).
-- Chris
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Orchid XP v8 wrote:
> I've been to the Xilinx website and looked at the various "development
> boards" they offer, and most of them seem to be around $2,000. Obviously
> I don't have that kind of money. I'll have to hunt around further to see
> if they offer anything at more sane prices.
Try Sparkfun:
http://www.sparkfun.com/commerce/product_info.php?products_id=8458
http://www.sparkfun.com/commerce/product_info.php?products_id=8460
http://www.sparkfun.com/commerce/product_info.php?products_id=8595
-- Chris
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>> Heh. Chris Cason. Is there anything he can't do? ;-)
>
> Get betas out on time?
OMG, PWN3D!!
[0wned BY YOURSELF! That's gotta be some uber-1337ness or something...]
> Also, keep an eye out for a CPLD devkit. CPLD's are (simply put) FPGA's
> with persistent configuration; i.e. you don't need to re-program them each
> time they are powered up.
OK, that's news. I was under the impression that an FPGA works something
like an EPROM - you use UV to erase it and then program in all the
circuit connections, and thereafter it just works.
>> Also, if memory serves me correctly, the Xilinx software is a free
>> download; they make their money from selling you the hardware.
>
> Like Altera they probably have an advanced version of the software that
> costs $$$.
Ah. Yeah, they probably have a free version, so you can see what it's
like, and then a super version that produces 10% more efficient layouts
or something. ;-)
> Back about ten years ago, even the base software version cost
> $1000 or so, but then they woke up to the fact that they are a hardware
> company and would probably sell more FPGA's if they didn't put barriers in
> the way of people designing with them. (This may seem obvious, but to bean
> counters, it apparently isn't: e.g. take the fact that Microsoft used to
> charge a few grand for the Windows 1.0 and 2.0 SDK's before realising
> they'd have more users if it was free).
Well, we charge people money = more money comes in. It seems like a
simple equation. Until you realise that the software is pretty much a
KILLER loss-leader... [It must surely cost them money to develop the
software of course, but it's fairly useless without the hardware.]
PS. I hear Xilinx bases their synthesis technology on Haskell. I don't
know how true that is...
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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>> I've been to the Xilinx website and looked at the various "development
>> boards" they offer, and most of them seem to be around $2,000. Obviously
>> I don't have that kind of money. I'll have to hunt around further to see
>> if they offer anything at more sane prices.
>
> Try Sparkfun:
>
> http://www.sparkfun.com/commerce/product_info.php?products_id=8458
> http://www.sparkfun.com/commerce/product_info.php?products_id=8460
> http://www.sparkfun.com/commerce/product_info.php?products_id=8595
That sounds more like it...
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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> OK, that's news. I was under the impression that an FPGA works something
> like an EPROM - you use UV to erase it and then program in all the
> circuit connections, and thereafter it just works.
Some are OTP (one time programmable) but most are flash based today.
Atmel makes CPLDs and FPGAs, too.
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>> OK, that's news. I was under the impression that an FPGA works something
>> like an EPROM - you use UV to erase it and then program in all the
>> circuit connections, and thereafter it just works.
>
> Some are OTP (one time programmable) but most are flash based today.
A PROM is OTP; an EPROM (Erasable PROM) can be reused.
An EPROM usually works by having a little lense over the die surface,
through which you fire UV radiation to cause chemical changes in the
chip material which either 'connects' or 'disconnects' circuit pathways,
thus forming a ROM.
I was under the impression that FPGAs work in the same way, except
instead of opening and closing contacts between data lines and the power
rails to make bit patterns, you actually connect and disconnect blocks
of circuitry to make a custom circuit configuration.
Of course, flash RAM uses chemical changes to permanently store data
too; you just don't need the lense and the UV radiation. But I didn't
think you could use that technology to physically change connections...
> Atmel makes CPLDs and FPGAs, too.
Right, OK.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Invisible <voi### [at] dev null> wrote:
> >> OK, that's news. I was under the impression that an FPGA works something
> >> like an EPROM - you use UV to erase it and then program in all the
> >> circuit connections, and thereafter it just works.
> >
> > Some are OTP (one time programmable) but most are flash based today.
>
> A PROM is OTP; an EPROM (Erasable PROM) can be reused.
True
>
> An EPROM usually works by having a little lense over the die surface,
> through which you fire UV radiation
Correct
> to cause chemical changes in the
> chip material which either 'connects' or 'disconnects' circuit pathways,
> thus forming a ROM.
Partly right. You erase with UV-radiation and program with a higher than usual
voltage
The programming works by trapping electrons inside an insulated gate of the
field effect transistors used to form the logic gates thus enabling the
connection. The erasing via UV gives the trapped electrons enough energy to
leave the gate and thus disabling the transistor
>
> I was under the impression that FPGAs work in the same way, except
> instead of opening and closing contacts between data lines and the power
> rails to make bit patterns, you actually connect and disconnect blocks
> of circuitry to make a custom circuit configuration.
THat's how it works. You have switch matrices which connect logic blocks and I/O
pins with each other and also configure the logic blocks.
>
> Of course, flash RAM uses chemical changes to permanently store data
> too;
Wrong. Works the same as in eeprom with electricity and trapped electrons
> you just don't need the lense and the UV radiation. But I didn't
> think you could use that technology to physically change connections...
>
you don't physically change connections but control switches in the connections.
> > Atmel makes CPLDs and FPGAs, too.
>
> Right, OK.
>
> --
> http://blog.orphi.me.uk/
> http://www.zazzle.com/MathematicalOrchid*
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Aydan wrote:
>> to cause chemical changes in the
>> chip material which either 'connects' or 'disconnects' circuit pathways,
>> thus forming a ROM.
>
> Partly right. You erase with UV-radiation and program with a higher than usual
> voltage
> The programming works by trapping electrons inside an insulated gate of the
> field effect transistors used to form the logic gates thus enabling the
> connection. The erasing via UV gives the trapped electrons enough energy to
> leave the gate and thus disabling the transistor
Interesting. I was under the impression that you use UV to program it
too - much the same way that you use a laser to burn a CD. (Obviously
you don't actually "burn" anything; you induce a chemical change in the
ink.)
>> Of course, flash RAM uses chemical changes to permanently store data
>> too;
>
> Wrong. Works the same as in eeprom with electricity and trapped electrons
Again, I was under the impression that you use a large current to
chemically change the components such that they now respond to
electricity differently, and that's how you store information.
>> you just don't need the lense and the UV radiation. But I didn't
>> think you could use that technology to physically change connections...
>
> you don't physically change connections but control switches in the connections.
Mmm, OK.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Invisible <voi### [at] devnull> wrote:
> Again, I was under the impression that you use a large current to
> chemically change the components such that they now respond to
> electricity differently, and that's how you store information.
PROMs work this way. Either by fuse and current or antifuse and voltage.
The change is more physical than chemical though.
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Invisible wrote:
> OK, that's news. I was under the impression that an FPGA works something
> like an EPROM - you use UV to erase it and then program in all the
> circuit connections, and thereafter it just works.
nope. FPGA == Field Programmable Gate Array, with the emphasis on 'Field'.
i.e. it has to be re-configured each time it powers on. typically used in
applications where the FPGA (for obvious reasons) is not needed to get the
system booted. (Actually you can attach serial EEPROM's to them to auto-
configure them at startup if you wish). Some newer FPGA's incorporate this
device into the FPGA itself. Configuration is done serially (basically just
a bitstream).
Here's a write-up on them anyhow:
http://en.wikipedia.org/wiki/Field-programmable_gate_array
-- Chris
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