FPGA Central

I'm looking at a possible application and trying to figure the relative costs of FPGA/CPLD versus
MCU.
I can do it with a microcontroller, but the only MCUs with the hardware I need (TFT LCD controller)
tend to come with lots of other stuff (ethernet, large flash, USB etc.) which I don't need.

As it can be hard to get 'real' prices of FPGAs without talking to all the distis etc. I wonder if
anyone can suggest parts to look at .

Rough reqiurement is :

Cheapest in 100x qtys for total solution inc. config and power supply ( from 3.3v supply), below
about GBP5(US$7.5)
Not BGA
Readly available : ex-stock or sensible leadtimes (2 weeks)
A couple of RAM blocks, around 1K byte each
about 60 IOs, all 3.3v
30MHz clock
Logic equivalent to around 100 CPLD macrocells
Free or low cost (<$500) design software

The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a bit over-specced.
CPLDs seem to get expensive above 72 cells and don't tend to have RAM

On May 13, 1:23*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
> I'm looking at a possible application and trying to figure the relative costs of FPGA/CPLD versus
> MCU.
> I can do it with a microcontroller, but the only MCUs with the hardware Ineed (TFT LCD controller)
> tend to come with lots of other stuff (ethernet, large flash, USB etc.) which I don't need.
>
> As it can be hard to get 'real' prices of FPGAs without talking to all the distis etc. I *wonder if
> anyone can suggest parts to look at .
>
> Rough reqiurement is :
>
> Cheapest in 100x qtys for total solution inc. config and power supply ( from 3.3v supply), below
> about GBP5(US$7.5)
> Not BGA
> Readly available : ex-stock or sensible leadtimes (2 weeks)
> A couple of RAM blocks, around 1K byte each
> about 60 IOs, all 3.3v
> 30MHz clock
> Logic equivalent to around 100 CPLD macrocells
> Free or low cost (<$500) design software
>
> The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a bit over-specced.
> CPLDs seem to get expensive above 72 cells and don't tend to have RAM

the IC you need is always the one that doesnt exist

S3-50AN prices do go below 4$ but not at 100x qty.
in 100x qty, it proabably more than your target price 7.5 (depend how
good you deal..)

Xilinx disties say: leadtime 12 weeks, call for order
Digikey has 4 pcs in stock

if you can deal with 2 KB RAM, then lattice EC1 is 6.1$ online price
available in stock, need spi flash, but it still cheap total price

but here XC3S50A would be better at about same price

Lattice XP3 is too expensive with online pricing.. $10, stock YES,
this is the IC that needs NO Externals, no flash, no LDO, just 3.3V !

Actel A3P060, is cheap, but again 2K RAM only

all the above have free tools
Altera doesnt seem to have devices that come to your desired price
range

hm.. call lattice disti, say you would like XP3-VQ100, but your BOM
limit is 7.5$ see what they say !!

if price doesnt come down, place xc3s50a-vq100 order on digikey, to
secure your devices before those are gone too (disties have no stock.
leadt=12w)

Antti

Mike Harrison <mike@whitewing.co.uk> writes:


> The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a bit over-specced.
> CPLDs seem to get expensive above 72 cells and don't tend to have RAM

I've used the Altera MAX-II a couple years ago and seem to remember
that they were pretty cheap.

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?

On May 13, 6:23*am, Mike Harrison <m...@whitewing.co.uk> wrote:

> The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a bit over-specced.
> CPLDs seem to get expensive above 72 cells and don't tend to have RAM

You might want to take a look at the following devices:

Lattice Semi - MachXO
Lattice Semi - Lattice XP / XP2
Altera - Cyclone II / III
Xilinx - Spartan 3A/AN
Silicon Blue - iCE 65

The MachXO looks to be exactly what you are after, although I don't
know what they cost. The Lattice tools come with an Synplify OEM
bundled, but I don't know what they cost or if older versions are
available for free. Hope that helps

I would consider the Igloo nano.
The Max II doesn't have embedded Ram.

Bert

On Wed, 13 May 2009 11:23:00 +0100
Mike Harrison <mike@whitewing.co.uk> wrote:

> I'm looking at a possible application and trying to figure the
> relative costs of FPGA/CPLD versus MCU.
> I can do it with a microcontroller, but the only MCUs with the
> hardware I need (TFT LCD controller) tend to come with lots of other
> stuff (ethernet, large flash, USB etc.) which I don't need.
>
> As it can be hard to get 'real' prices of FPGAs without talking to
> all the distis etc. I wonder if anyone can suggest parts to look at .
>
> Rough reqiurement is :
>
> Cheapest in 100x qtys for total solution inc. config and power supply
> ( from 3.3v supply), below about GBP5(US$7.5)
> Not BGA
> Readly available : ex-stock or sensible leadtimes (2 weeks)
> A couple of RAM blocks, around 1K byte each
> about 60 IOs, all 3.3v
> 30MHz clock
> Logic equivalent to around 100 CPLD macrocells
> Free or low cost (<$500) design software
>
> The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a
> bit over-specced. CPLDs seem to get expensive above 72 cells and
> don't tend to have RAM
>
>

When I did some pricing pusharounds on the 3As, I came to the
conclusion that it was cheaper to get the 3A and an external SPI
flash than to get the 3AN. It also allows you more choices in the FPGA
packaging.

--
Rob Gaddi, Highland Technology
Email address is currently out of order

On May 13, 4:50*pm, smith...@gmail.com wrote:
> On May 13, 6:23*am, Mike Harrison <m...@whitewing.co.uk> wrote:
>
> > The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a bit over-specced.
> > CPLDs seem to get expensive above 72 cells and don't tend to have RAM
>
> You might want to take a look at the following devices:
>
> Lattice Semi - MachXO
devices with embedded RAM too expensive

> Lattice Semi - Lattice XP / XP2
I already suggested, but even XP3-vq100 is too expensive with standard
pricing

> Altera - Cyclone II / III
way too expensive for target budget

> Xilinx - Spartan 3A/AN
nothing in stock?
AN too expensive, A, maybe

> Silicon Blue - iCE 65
also too expensive for the volume/target price

>
> The MachXO looks to be exactly what you are after, although I don't
> know what they cost. *The Lattice tools come with an Synplify OEM
> bundled, but I don't know what they cost or if older versions are
> available for free. Hope that helps

..

On Wed, 13 May 2009 03:58:40 -0700 (PDT), "Antti.Lukats@googlemail.com"
<Antti.Lukats@googlemail.com> wrote:

>On May 13, 1:23*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
>> I'm looking at a possible application and trying to figure the relative costs of FPGA/CPLD versus
>> MCU.
>> I can do it with a microcontroller, but the only MCUs with the hardware I need (TFT LCD controller)
>> tend to come with lots of other stuff (ethernet, large flash, USB etc.) which I don't need.
>>
>> As it can be hard to get 'real' prices of FPGAs without talking to all the distis etc. I *wonder if
>> anyone can suggest parts to look at .
>>
>> Rough reqiurement is :
>>
>> Cheapest in 100x qtys for total solution inc. config and power supply ( from 3.3v supply), below
>> about GBP5(US$7.5)
>> Not BGA
>> Readly available : ex-stock or sensible leadtimes (2 weeks)
>> A couple of RAM blocks, around 1K byte each
>> about 60 IOs, all 3.3v
>> 30MHz clock
>> Logic equivalent to around 100 CPLD macrocells
>> Free or low cost (<$500) design software
>>
>> The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a bit over-specced.
>> CPLDs seem to get expensive above 72 cells and don't tend to have RAM
>
>the IC you need is always the one that doesnt exist
>
>S3-50AN prices do go below 4$ but not at 100x qty.
>in 100x qty, it proabably more than your target price 7.5 (depend how
>good you deal..)
>
>Xilinx disties say: leadtime 12 weeks, call for order
>Digikey has 4 pcs in stock
>
>if you can deal with 2 KB RAM, then lattice EC1 is 6.1$ online price
>available in stock, need spi flash, but it still cheap total price
>
>but here XC3S50A would be better at about same price
>
>Lattice XP3 is too expensive with online pricing.. $10, stock YES,
>this is the IC that needs NO Externals, no flash, no LDO, just 3.3V !
>
>Actel A3P060, is cheap, but again 2K RAM only
>
>all the above have free tools
>Altera doesnt seem to have devices that come to your desired price
>range
>
>hm.. call lattice disti, say you would like XP3-VQ100, but your BOM
>limit is 7.5$ see what they say !!
>
>if price doesnt come down, place xc3s50a-vq100 order on digikey, to
>secure your devices before those are gone too (disties have no stock.
>leadt=12w)
>
>Antti

Thanks for the suggestions - the Lattice EC1 looks a pretty good fit on all counts - RAM is 'only
just' enough, but means I'm not paying for stuff I don't need.

I even found a cheap eval board for it :
http://www.msc-toolguide.com/lattice...ion-board.html

On May 13, 1:45*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
> On Wed, 13 May 2009 03:58:40 -0700 (PDT), "Antti.Luk...@googlemail.com"
>
>
>
> <Antti.Luk...@googlemail.com> wrote:
> >On May 13, 1:23*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
> >> I'm looking at a possible application and trying to figure the relative costs of FPGA/CPLD versus
> >> MCU.
> >> I can do it with a microcontroller, but the only MCUs with the hardware I need (TFT LCD controller)
> >> tend to come with lots of other stuff (ethernet, large flash, USB etc.) which I don't need.
>
> >> As it can be hard to get 'real' prices of FPGAs without talking to allthe distis etc. I *wonder if
> >> anyone can suggest parts to look at .
>
> >> Rough reqiurement is :
>
> >> Cheapest in 100x qtys for total solution inc. config and power supply ( from 3.3v supply), below
> >> about GBP5(US$7.5)
> >> Not BGA
> >> Readly available : ex-stock or sensible leadtimes (2 weeks)
> >> A couple of RAM blocks, around 1K byte each
> >> about 60 IOs, all 3.3v
> >> 30MHz clock
> >> Logic equivalent to around 100 CPLD macrocells
> >> Free or low cost (<$500) design software
>
> >> The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a bitover-specced.
> >> CPLDs seem to get expensive above 72 cells and don't tend to have RAM
>
> >the IC you need is always the one that doesnt exist
>
> >S3-50AN prices do go below 4$ but not at 100x qty.
> >in 100x qty, it proabably more than your target price 7.5 (depend how
> >good you deal..)
>
> >Xilinx disties say: leadtime 12 weeks, call for order
> >Digikey has 4 pcs in stock
>
> >if you can deal with 2 KB RAM, then lattice EC1 is 6.1$ online price
> >available in stock, need spi flash, but it still cheap total price
>
> >but here XC3S50A would be better at about same price
>
> >Lattice XP3 is too expensive with online pricing.. $10, stock YES,
> >this is the IC that needs NO Externals, no flash, no LDO, just 3.3V !
>
> >Actel A3P060, is cheap, but again 2K RAM only
>
> >all the above have free tools
> >Altera doesnt seem to have devices that come to your desired price
> >range
>
> >hm.. call lattice disti, say you would like XP3-VQ100, but your BOM
> >limit is 7.5$ see what they say !!
>
> >if price doesnt come down, place xc3s50a-vq100 order on digikey, to
> >secure your devices before those are gone too (disties have no stock.
> >leadt=12w)
>
> >Antti
>
> Thanks for the suggestions - the Lattice EC1 looks a pretty good fit on all counts - RAM is 'only
> just' enough, but means I'm not paying for stuff I don't need.
>
> I even found a cheap eval board for it :http://www.msc-toolguide.com/lattice...ion-board.html

I had to do this same search last year and I found very little that
would suit my needs... in fact, I found exactly one part that really
was suited to the job. The problem you will find with most parts is
not actually the price of the part itself, but rather the price of the
package. The FPGA vendors will attest to the fact that the pricing of
these parts at the low end is mostly governed by testing which is in
tern dominated by the cost of testing the I/Os. So the lower the pin
count, the cheaper the part.

I also has space constraints which in the end led me to the Lattice XP
in the 100 pin QFP package. It is about $10 (or maybe a squeak less)
at qty 100 and was the only comparable part in this price range.
Remember that the XP has internal Flash and the ram parts do not. I
remember that some ram based FPGA vendors would jump up and down and
insist that ram was the only way to go when considering the advantages
of die size and how it would impact the cost. I guess that really is
not the whole picture is it?

I am using the LFXP3C-3TN100C which is 3.3 volt only power with 63 or
64 I/Os, IIRC, commercial temp and the slowest speed grade. If you
sweet talk you local disti or Lattice rep, I bet you can get them for
$9. I am actually using contract turnkey assembly, so I don't know
exactly what they are paying, but my local guy has quoted me $9.50 for
preprogrammed parts.

The only issue may be availability, but then I have never found *any*
FPGA that they maintain significant amounts of stock at all times.
Mouser sells Lattice, but the inventory is mostly at Lattice and is
drop shipped.

I did not find one other part that was better in any regard and I
don't recall finding any others that met all these constraints... but
then it was a year ago...

Rick

On Wed, 13 May 2009 12:36:26 -0700 (PDT), rickman <gnuarm@gmail.com> wrote:

>On May 13, 1:45*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
>> On Wed, 13 May 2009 03:58:40 -0700 (PDT), "Antti.Luk...@googlemail.com"
>>
>>
>>
>> <Antti.Luk...@googlemail.com> wrote:
>> >On May 13, 1:23*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
>> >> I'm looking at a possible application and trying to figure the relative costs of FPGA/CPLD versus
>> >> MCU.
>> >> I can do it with a microcontroller, but the only MCUs with the hardware I need (TFT LCD controller)
>> >> tend to come with lots of other stuff (ethernet, large flash, USB etc.) which I don't need.
>>
>> >> As it can be hard to get 'real' prices of FPGAs without talking to all the distis etc. I *wonder if
>> >> anyone can suggest parts to look at .
>>
>> >> Rough reqiurement is :
>>
>> >> Cheapest in 100x qtys for total solution inc. config and power supply ( from 3.3v supply), below
>> >> about GBP5(US$7.5)
>> >> Not BGA
>> >> Readly available : ex-stock or sensible leadtimes (2 weeks)
>> >> A couple of RAM blocks, around 1K byte each
>> >> about 60 IOs, all 3.3v
>> >> 30MHz clock
>> >> Logic equivalent to around 100 CPLD macrocells
>> >> Free or low cost (<$500) design software
>>
>> >> The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a bit over-specced.
>> >> CPLDs seem to get expensive above 72 cells and don't tend to have RAM
>>
>> >the IC you need is always the one that doesnt exist
>>
>> >S3-50AN prices do go below 4$ but not at 100x qty.
>> >in 100x qty, it proabably more than your target price 7.5 (depend how
>> >good you deal..)
>>
>> >Xilinx disties say: leadtime 12 weeks, call for order
>> >Digikey has 4 pcs in stock
>>
>> >if you can deal with 2 KB RAM, then lattice EC1 is 6.1$ online price
>> >available in stock, need spi flash, but it still cheap total price
>>
>> >but here XC3S50A would be better at about same price
>>
>> >Lattice XP3 is too expensive with online pricing.. $10, stock YES,
>> >this is the IC that needs NO Externals, no flash, no LDO, just 3.3V !
>>
>> >Actel A3P060, is cheap, but again 2K RAM only
>>
>> >all the above have free tools
>> >Altera doesnt seem to have devices that come to your desired price
>> >range
>>
>> >hm.. call lattice disti, say you would like XP3-VQ100, but your BOM
>> >limit is 7.5$ see what they say !!
>>
>> >if price doesnt come down, place xc3s50a-vq100 order on digikey, to
>> >secure your devices before those are gone too (disties have no stock.
>> >leadt=12w)
>>
>> >Antti
>>
>> Thanks for the suggestions - the Lattice EC1 looks a pretty good fit on all counts - RAM is 'only
>> just' enough, but means I'm not paying for stuff I don't need.
>>
>> I even found a cheap eval board for it :http://www.msc-toolguide.com/lattice...ion-board.html
>
>I had to do this same search last year and I found very little that
>would suit my needs... in fact, I found exactly one part that really
>was suited to the job. The problem you will find with most parts is
>not actually the price of the part itself, but rather the price of the
>package. The FPGA vendors will attest to the fact that the pricing of
>these parts at the low end is mostly governed by testing which is in
>tern dominated by the cost of testing the I/Os. So the lower the pin
>count, the cheaper the part.

And nobody seems to do low pin-count FPGAs, and CPLDs seem to have a big price jump above 72
macrocells which I've never quite understood - there appears to be a gaping hole between the $2 CPLD
and the $8ish FPGA.

> I remember that some ram based FPGA vendors would jump up and down and
>insist that ram was the only way to go when considering the advantages
>of die size and how it would impact the cost. I guess that really is
>not the whole picture is it?

Well the pricing of S3A+SPI flash compared to S3AN seems to support this...
Single-chip and single-supply are nice, but not if the additional cost is several times that of
external regulator/flash!


>The only issue may be availability, but then I have never found *any*
>FPGA that they maintain significant amounts of stock at all times.
>Mouser sells Lattice, but the inventory is mostly at Lattice and is
>drop shipped.

Farnell also list several Lattice devices, so availability appears to at least be better than
Xilinx.

On May 13, 10:23*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
> I'm looking at a possible application and trying to figure the relative costs of FPGA/CPLD versus
> MCU.
> I can do it with a microcontroller, but the only MCUs with the hardware Ineed (TFT LCD controller)
> tend to come with lots of other stuff (ethernet, large flash, USB etc.) which I don't need.

If you can find a chip that does the task, that's normally going to be
cheaper than a FPGA.
(even with unused bits )

Or, find a uC that is close, and add a smaller Prog Logic device to
stretch the peripherals.
Streaming SPI-CPLD can add quite smart 'external peripherals'.
The uC have Code-flash built in, as well as Analog features.

>
> As it can be hard to get 'real' prices of FPGAs without talking to all the distis etc. I *wonder if
> anyone can suggest parts to look at .
>
> Rough reqiurement is :
>
> Cheapest in 100x qtys for total solution inc. config and power supply ( from 3.3v supply), below
> about GBP5(US$7.5)
> Not BGA
> Readly available : ex-stock or sensible leadtimes (2 weeks)
> A couple of RAM blocks, around 1K byte each
> about 60 IOs, all 3.3v
> 30MHz clock
> Logic equivalent to around 100 CPLD macrocells
> Free or low cost (<$500) design software
>
> The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a bit over-specced.
> CPLDs seem to get expensive above 72 cells and don't tend to have RAM

The two choices do not really seem to overlap here ? - you have a
quite small logic block, and no
mention of any processor on the 2nd choice ?

100 macrocells is viable in CPLD (384/512 tend to not stack up), and a
device like
ATF1508RE (128MC 3.3V SingleSupply) is $3.90/100+ at Digikey.
You may be able to add SPI RAM - 32Kx8 is $1.09/100+

Bert_Paris <do_not_spam@me.com> writes:

> I would consider the Igloo nano.
> The Max II doesn't have embedded Ram.

That's true, but it has a quite a few registers (240-2k+ LE's). I see
from some of the later posts that 2K RAM is a minimin requirement
which will rule out the Max-II unless an external RAM is used.

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?

On Wed, 13 May 2009 16:45:05 -0700 (PDT), -jg <Jim.Granville@gmail.com> wrote:

>On May 13, 10:23*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
>> I'm looking at a possible application and trying to figure the relative costs of FPGA/CPLD versus
>> MCU.
>> I can do it with a microcontroller, but the only MCUs with the hardware I need (TFT LCD controller)
>> tend to come with lots of other stuff (ethernet, large flash, USB etc.) which I don't need.
>
>If you can find a chip that does the task, that's normally going to be
>cheaper than a FPGA.
>(even with unused bits )

In many cases I'd agree that this is true, but in this particular one, almost all the other parts of
the MCU, including most of the 512K of flash, ethernet,USB,CAN,SD etc. etc. and a lot of pins aren't
needed.

>Or, find a uC that is close, and add a smaller Prog Logic device to
>stretch the peripherals.
>Streaming SPI-CPLD can add quite smart 'external peripherals'.
>The uC have Code-flash built in, as well as Analog features.

Again in many cases this would be a good solution but probably not here.
What I'm looking at is the cheapest way to drive a large number (potentially hundreds) of
distributed TFT (PSP) displays with local SDRAM and/or NAND flash storage for a few tens to hundreds
of frames, with a relatively a low bandwidth network of some sort to update content in non-realtime,
and switch the display between stored frames realtime. The aim is to minimise the cost per node as
much as possible.
The NXP LPC2478's LCD controller is fine, but the memory bus will be a bit of a bottleneck,
especially with the NAND flash option, as data needs to pass over the bus 3 times. Unfortunately
for reasons I can't fathom, NXP forgot to put a SPI flash load option in the bootloader of the
flashless 2470 version - it would in principle to load it using the ISP interface at startup but
it's a bit messy. And it would still be more expensive than the Lattice EC1 option.
At some point I may look at the NXP ARM9 LCD part which can load from SPI but it's in a BGA package
and this project is still at a small-scale speculative proof-of-concept stage so prototyping costs
need to be minimised.

The problem for both NAND and SDRAM is getting a contiguous stream of data to the LCD between the
hsyncs- NAND's 25uS page read time, and the SDRAM page sizes are problems which can be solved easily
once you have enough RAM for a 1-line FIFO buffer in an FPGA. It also makes it more potentially
viable to drive 2 displays per controller, which would slash the per-node cost.
The FPGA also provides more flexibility on the interface between units - e.g. faster SPI or UART
rates than the MCU could handle. If there are enough spare pins to commit an IO bank, even fast
LVDS between nodes could be an option,

>> The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a bit over-specced.
>> CPLDs seem to get expensive above 72 cells and don't tend to have RAM
>
>The two choices do not really seem to overlap here ? - you have a
>quite small logic block, and no
>mention of any processor on the 2nd choice ?

This was more of a general comment than one specific to this app. there is a big cost jump above 72
MC's that makes them not much cheaper than FPGAs.
I did start looking at whether a CPLD solution would be viable, hiding flash read/SDRAM setup inside
the line syncs but the timings & addressing don't quite look like they would work, and you'd need
too many macrocells to add an external SRAM.

>100 macrocells is viable in CPLD (384/512 tend to not stack up), and a
>device like
>ATF1508RE (128MC 3.3V SingleSupply) is $3.90/100+ at Digikey.
>You may be able to add SPI RAM - 32Kx8 is $1.09/100+

Interesting - I'd not noticed that one - I've used Atmel CPLDs in the distant past but had sort of
forgotten that they still did them as they don't seem promote them very much these days..!

The MAX II is a nice device, but the lack of RAM does let it down
some. The on board slow flash gives 1K EEPROM but this is not large
enough for many designs. SRAM chips are quite cheap for small
capacities, but there needs to be a pin budget of around 20+ pins to
interface to them.

RAM is the only thing 'missing' from the MAX IIZ. The smaller die size
argument is a bit silly, 1/4 of the macrocell area could be replaced
by a reasonable self refresh DRAM, with single ported access.

cheers jacko

Jacko <jackokring@gmail.com> writes:

> capacities, but there needs to be a pin budget of around 20+ pins to

Not so if a serial RAM fits your bandwidth and latency requirements:

http://ww1.microchip.com/downloads/e...Doc/22127a.pdf


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?

On May 13, 6:31*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
> On Wed, 13 May 2009 12:36:26 -0700 (PDT), rickman <gnu...@gmail.com> wrote:
> >On May 13, 1:45*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
> >> On Wed, 13 May 2009 03:58:40 -0700 (PDT), "Antti.Luk...@googlemail.com"
>
> >> <Antti.Luk...@googlemail.com> wrote:
> >> >On May 13, 1:23*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
> >> >> I'm looking at a possible application and trying to figure the relative costs of FPGA/CPLD versus
> >> >> MCU.
> >> >> I can do it with a microcontroller, but the only MCUs with the hardware I need (TFT LCD controller)
> >> >> tend to come with lots of other stuff (ethernet, large flash, USB etc.) which I don't need.
>
> >> >> As it can be hard to get 'real' prices of FPGAs without talking to all the distis etc. I *wonder if
> >> >> anyone can suggest parts to look at .
>
> >> >> Rough reqiurement is :
>
> >> >> Cheapest in 100x qtys for total solution inc. config and power supply ( from 3.3v supply), below
> >> >> about GBP5(US$7.5)
> >> >> Not BGA
> >> >> Readly available : ex-stock or sensible leadtimes (2 weeks)
> >> >> A couple of RAM blocks, around 1K byte each
> >> >> about 60 IOs, all 3.3v
> >> >> 30MHz clock
> >> >> Logic equivalent to around 100 CPLD macrocells
> >> >> Free or low cost (<$500) design software
>
> >> >> The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a bit over-specced.
> >> >> CPLDs seem to get expensive above 72 cells and don't tend to have RAM
>
> >> >the IC you need is always the one that doesnt exist
>
> >> >S3-50AN prices do go below 4$ but not at 100x qty.
> >> >in 100x qty, it proabably more than your target price 7.5 (depend how
> >> >good you deal..)
>
> >> >Xilinx disties say: leadtime 12 weeks, call for order
> >> >Digikey has 4 pcs in stock
>
> >> >if you can deal with 2 KB RAM, then lattice EC1 is 6.1$ online price
> >> >available in stock, need spi flash, but it still cheap total price
>
> >> >but here XC3S50A would be better at about same price
>
> >> >Lattice XP3 is too expensive with online pricing.. $10, stock YES,
> >> >this is the IC that needs NO Externals, no flash, no LDO, just 3.3V !
>
> >> >Actel A3P060, is cheap, but again 2K RAM only
>
> >> >all the above have free tools
> >> >Altera doesnt seem to have devices that come to your desired price
> >> >range
>
> >> >hm.. call lattice disti, say you would like XP3-VQ100, but your BOM
> >> >limit is 7.5$ see what they say !!
>
> >> >if price doesnt come down, place xc3s50a-vq100 order on digikey, to
> >> >secure your devices before those are gone too (disties have no stock.
> >> >leadt=12w)
>
> >> >Antti
>
> >> Thanks for the suggestions - the Lattice EC1 looks a pretty good fit on all counts - RAM is 'only
> >> just' enough, but means I'm not paying for stuff I don't need.
>
> >> I even found a cheap eval board for it :http://www.msc-toolguide.com/lattice...ion-board.html
>
> >I had to do this same search last year and I found very little that
> >would suit my needs... in fact, I found exactly one part that really
> >was suited to the job. *The problem you will find with most parts is
> >not actually the price of the part itself, but rather the price of the
> >package. *The FPGA vendors will attest to the fact that the pricing of
> >these parts at the low end is mostly governed by testing which is in
> >tern dominated by the cost of testing the I/Os. *So the lower the pin
> >count, the cheaper the part.
>
> And nobody seems to do low pin-count FPGAs, and CPLDs seem to have a big price jump above 72
> macrocells which I've never quite understood - there appears to be a gaping hole between the $2 CPLD
> and the $8ish FPGA.

I used a 256 cell CPLD in a project once and yes, it was a bit
pricey. I think the routing of these parts goes up very quickly as
the size increases. They don't have the same routing structure as an
FPGA and that may be what drives up the cost and limits the size.


> > *I remember that some ram based FPGA vendors would jump up and down and
> >insist that ram was the only way to go when considering the advantages
> >of die size and how it would impact the cost. *I guess that really is
> >not the whole picture is it?
>
> Well the pricing of S3A+SPI flash compared to S3AN seems to support this....
> Single-chip and single-supply are nice, but not if the additional cost isseveral times that of
> external regulator/flash!

What pricing do you have for these parts? I'm not clear on which are
saying is the expensive option. Both of the Spartan devices use two
die, one for the FPGA and one for the flash. The S3AN parts just put
them both in the same package. That is how they did it when they came
out; I don't think they have changed this. According to Xlinx Flash
is just not compatible with their small geometry process.


> >The only issue may be availability, but then I have never found *any*
> >FPGA that they maintain significant amounts of stock at all times.
> >Mouser sells Lattice, but the inventory is mostly at Lattice and is
> >drop shipped.
>
> Farnell also list several Lattice devices, so availability appears to at least be better than
> Xilinx.

Xilinx should be as available as the others, no?

Rick

Mike Harrison wrote:
> I'm looking at a possible application and trying to figure the relative costs of FPGA/CPLD versus
> MCU.
> I can do it with a microcontroller, but the only MCUs with the hardware I need (TFT LCD controller)
> tend to come with lots of other stuff (ethernet, large flash, USB etc.) which I don't need.
>
> As it can be hard to get 'real' prices of FPGAs without talking to all the distis etc. I wonder if
> anyone can suggest parts to look at .
>
> Rough reqiurement is :
>
> Cheapest in 100x qtys for total solution inc. config and power supply ( from 3.3v supply), below
> about GBP5(US$7.5)
> Not BGA
> Readly available : ex-stock or sensible leadtimes (2 weeks)
> A couple of RAM blocks, around 1K byte each
> about 60 IOs, all 3.3v
> 30MHz clock
> Logic equivalent to around 100 CPLD macrocells
> Free or low cost (<$500) design software
>
> The Xilinx S3A/AN-50 is the cheapest I've found so far, but is a a bit over-specced.
> CPLDs seem to get expensive above 72 cells and don't tend to have RAM
>
Take a look at Xilinx Spartan 2E, they are just a bit more expensive,
but no problem on availability.

I buy them 25 at a time, for about US $12 each. You might get them down
about where you want the price in 100 Pc quantity.
I use the TQ144 package, no problem hand soldering or cheap reflow.

Jon

On May 14, 9:20*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
> What I'm looking at is the cheapest way to drive a large number (potentially hundreds) of
> distributed TFT (PSP) displays with local SDRAM and/or NAND flash storagefor a few tens to hundreds
> of frames, with a relatively a low bandwidth network of some sort to update content in non-realtime,
> and switch the display between stored frames realtime. The aim is to minimise the cost per node as
> much as possible.

Ah, so you need many slaves, and the smarts can be elsewhere.

I found some info on TFT(PSP), [9MHz, 8+8+8 Colour] and it seems the
simplest solution would be a 32 bit wide SDRAM
and a CPLD, and 128MC should be plenty.
- I don't see you need a line-ram in a SDRAM playback scheme (tho the
Qimonda SDRAM data I had was poor ).

Run the CPLD at >> 9MHz (or whatever is needed to interleave access),
and a simple BUS connect CPLD.SDRAM.TFT,
then something like nibble-wide SPI to link all the slaves.

We have done simple cascade shifters, when doing similar designs - all
slaves chain, and here ~13 clocks are needed per slave node.
>
> Interesting - I'd not noticed that one - I've used Atmel CPLDs in the distant past but had sort of
> forgotten that they still did them as they don't seem promote them very much these days..!

They are poor on promotion, which is a shame as they have nice parts.

-jg

>> Well the pricing of S3A+SPI flash compared to S3AN seems to support this...
>> Single-chip and single-supply are nice, but not if the additional cost is several times that of
>> external regulator/flash!
>
>What pricing do you have for these parts? I'm not clear on which are
>saying is the expensive option.

Last time I looked at pricing on Digikey, the AN was noticeably more then the A plus the cost of an
SPI flash - this was a while ago though.


>> >The only issue may be availability, but then I have never found *any*
>> >FPGA that they maintain significant amounts of stock at all times.
>> >Mouser sells Lattice, but the inventory is mostly at Lattice and is
>> >drop shipped.
>>
>> Farnell also list several Lattice devices, so availability appears to at least be better than
>> Xilinx.
>
>Xilinx should be as available as the others, no?

Findchips.com search for xc3s50a shows 7 lines in stock at 2 distributors
Findchips.com search for LFEC1 (Lattice) shows about 20 lines in stock at 4 distis.

On Thu, 14 May 2009 15:05:17 -0700 (PDT), -jg <Jim.Granville@gmail.com> wrote:

>On May 14, 9:20*pm, Mike Harrison <m...@whitewing.co.uk> wrote:
>> What I'm looking at is the cheapest way to drive a large number (potentially hundreds) of
>> distributed TFT (PSP) displays with local SDRAM and/or NAND flash storage for a few tens to hundreds
>> of frames, with a relatively a low bandwidth network of some sort to update content in non-realtime,
>> and switch the display between stored frames realtime. The aim is to minimise the cost per node as
>> much as possible.
>
>Ah, so you need many slaves, and the smarts can be elsewhere.
>
>I found some info on TFT(PSP), [9MHz, 8+8+8 Colour] and it seems the
>simplest solution would be a 32 bit wide SDRAM
>and a CPLD, and 128MC should be plenty.
> - I don't see you need a line-ram in a SDRAM playback scheme (tho the
>Qimonda SDRAM data I had was poor ).

One possible solution I considered was SDRAM using page-reads, one per displayed line. However the
page size means it would need 2x 8-wide SDRAMS as the x16 device page size on a 64M SDRAM is only
256 bytes ( I've decided that the difference between 16 bit 5:6:5 and 24 bit display is negligible -
content can be pre-dithered if necessary).
However although this would work OK for reads, writes to SDRAM would be limited to the vertical
blanking interval (12 lines), so the sending of data would need to be synced to this, and bandwidth
would be limited - without a local buffer you'd need high peak bandwidth which would be idle most of
the time.
Having a couple of 512-pixel buffers (one for read, one for write) means data can be read and
written much more freely, as you can do a page read from SDRAM to the buffer at, say, twice the
pixel clock, leaving 50% of RAM bandwidth available for writes, and no sync constraints on write
data - the only constraint is the rate of data transmission, which is easily regulated. It would
also remove the 1 line/1 page constraint so RAM use could be more efficient, although wasting 32 out
of 512 words may be worthwhile to simplify the control logic.
Given a suitably fast network link, updates at full-frame rate would be possible, and the whole
system becomes a lot more flexible.