[sdiy] Actel Fusion

[Scott Gravenhorst]

"Barry Klein" <Barry.L.Klein at wdc.com> wrote:
>Hi Scott,
>On the multiplier subject - they do have an app note covering it:
>http://www.actel.com/documents/Fusion_Multipliers_AN.pdf
>but heck if I know what it all means... :-)

That's a description of how to use LUT resources to create a multiplier, basically a ROM
as a product lookup table with the address lines as the inputs.  This uses "tiles" which
I assume are like Xilinx "slices".  Also, the performance isn't stellar, they give clock
rates for several configs up to 8 bit x 8 bit multipliers ranging from 63 MHz to 293 MHz,
with tile usage from 0 to 431 and some configs use RAM as well.  These are small
multipliers and you'd need to cascade these to build wider ones.  Cascading would ellicit
further performance hits.  The Spartan-3E has 20 dedicated hardware multipliers each
which are 18 bit x 18 bit signed and operate at about 200 MHz.  Using a dedicated
multiplier requires no slice usage, but does disallow use of the associated block RAM
(and vice versa).  You can also build multipliers out of LUT resources with the Spartan
with similar results.



>-----Original Message-----
>From: synth-diy-bounces at dropmix.xs4all.nl
>[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Scott Gravenhorst
>Sent: Friday, January 25, 2008 9:35 AM
>To: synth-diy at dropmix.xs4all.nl
>Subject: Re: [sdiy] Actel Fusion
>
>"Barry Klein" <Barry.L.Klein at wdc.com> wrote:
>>Another platform that may have potential for us is the Actel Fusion.  I
>>guess it has been out for some time but today is the first I had heard of
>>it.  Basically an FPGA along with analog modules/channels and conversion.
>>Here is a waveform generator app note:
>>http://www.actel.com/documents/Fusion_Waveform_TB.pdf
>>I wonder how much of the part this takes up?  There are temperature,
>>voltage, and current sensing circuits in the chip as well.  Anyone have any
>>experience with it and have an idea of chip costs and the fusion starter
>kit
>>cost?  They talk of a choice between ARM and 8051 soft core processor for
>>the FPGA too.  Would that be free or?  Got an idea of part costs?
>
>Data here: http://www.actel.com/products/fusion/
>
>The starter kit uses the 600K gate part.  "Distributed" RAM looks low at
>108K bits and
>block RAM at 24 blocks by 4608 bits also small at about 110K bits.  There is
>no mention
>of dedicated hardware multipliers - a serious drawback for DSP.  The starter
>kit
>literature mentions analog inputs, but I see nothing about DAC, only ADC...
>
>Also, with  CoreMP7S, it seems that only 1/2 of the flipflops are usable and
>with 
>CoreMP7Sd only 1/3 are usable.  Seems limiting to me unless you make very
>good tight use
>of the core - which if I understand this, is an embedded processor and not
>necessary very
>efficient for a synth-on-a-chip system.  
>
>To compare - the Xilinx Spartan-3E Starter Kit can be endowed with a variety
>of MCU cores
>such as the cost free PicoBlaze.  My experience says that PicoBlaze makes a
>very nice
>full featured MIDI receiver and synth controller and it uses about 1% of the
>slice
>resources of the FPGA and only one block RAM leaving MOST of the FPGA free
>for your synth
>hardware.  MicroBlaze is a larger more powerful MCU, but is quite overkill
>for a MIDI
>controller.  (My assembler code MIDI controller uses less than 1/2 of it's
>"ROM" (less
>than 500 instructions), so there is room for all kinds of features).
>
>Just my opinion.
>
>-- ScottG
>
>-------------------------------------------------------------
>
>-- Scott Gravenhorst
>-- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
>-- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
>-- FatMan: home1.gte.net/res0658s/fatman/
>-- NonFatMan: home1.gte.net/res0658s/electronics/
>-- When the going gets tough, the tough use the command line.
>
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>

-- ScottG

-------------------------------------------------------------

-- Scott Gravenhorst
-- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
-- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- When the going gets tough, the tough use the command line.