[Coco] Cococompatible monitors...

[gene heskett]

On Monday, July 04, 2011 01:34:58 PM John Kent did opine:

> Hi Gene,
> 
> On 3/07/2011 11:37 PM, gene heskett wrote:
> > On Sunday, July 03, 2011 09:13:16 AM John Kent did opine:
> > 
> > The gime's pallette is somehow extracted from a 2 bit d/a on each
> > color, for a 4 level per color lashup.  Now if this FPGA in a Spartan
> > 3 could just drop into the gime socket, I could get interested.  Real
> > interested. Running a 63C09, and a 2 meg disto memory kit, all on an
> > old AT power supply, I have nearly zero heat, the gime is the warmest
> > chip in it, and the power use in that socket could go up to several
> > watts with a suitable heat sink.
> 
> The Spartan 3 would not be a direct drop in. It would need to be mounted
> on a daughter board with some sort of pin header arrangement for the
> GIME chip. It would also need on board 5v to 3.3V bus switches to make
> it 5V compatible as well as some regulators, bypass caps and so on and
> perhaps an oscillator chip if the GIME has a crystal oscillator circuit
> built in.
> 
> Power consumption and heat dissipation shouldn't be a problem at the
> sort of clock rates the GIME chip is running at. Most low cost FPGA
> boards running with a 50MHz clock don't require cooling, in fact the
> FPGAs in the systems I have designed barely get warm. The entire DE1
> board can be powered by a USB socket, i.e. uses less than 500mA or less
> than 2.5W and that includes all the peripheral chips such as SDRAM,
> SRAM, Flash, RS232 and audio codecs and so on. Most of this is running
> off 3.3V so about 1/3 of the power is dissipated in the regulators.
> 
> I'm not sure about the GIME chip, but the 6809 I think was originally
> NMOS.
> 
> There is a Spartan 3 power calculator here:
> 
> http://www.origin.xilinx.com/cgi-bin/power_tool/power_Spartan3
> 
> The Spartan 3 runs off 1.2V, 2.5V and 3.3V by the looks of it. Current
> consumption at a guess would be under 100mA depending on what clock
> rates the logic was working at. Not all of it would be working at 25MHz.
> You need to synthesize the design to get an accurate estimate of the
> power consumption.
> 
> John.
> 
> > I am well aware of the limitations imposed by the coco's OEM power
> > supply and regulator, which could not support that power usage
> > increase without active cooling.  That however is also adjustable, I
> > have done it a couple of times now.  That very inefficient analog
> > design is 90% of the emitted heat in a box stock coco.  It can drive
> > a small 12 volt dc fan from the output of the rectifier, and this is
> > a huge help in maintaining reasonable internal temps.  Whether that
> > additional 150 ma is still within the design envelope of that
> > transformer I don't know, but I have a coco2 and a coco3 equipt with
> > fans, and the coco2 ran 24/7 for 13 years, with 2 drive controller
> > failures.  The lack of a 3 pin power plug on the drive boxes and the
> > coco2 meant that when the studio tower was being used as a lightning
> > rod by mother nature, the resultant EMP surges were pretty hard on
> > the controller.  I eventually married them all together with copper
> > braid, grounded to the rack.
> > 
> > 
> > Cheers, gene

And this DE1 board I assume has a cost of?  URL please John.

Cheers, gene
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