On Wed, 13 May 2009 03:58:40 -0700 (PDT), "
[email protected]"
<
[email protected]> 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