FPPTA?

[Adam Megacz]

Field Programmable Pass Transistor Array.

Is there such a thing? I'm imagining even something that's NMOS-only
with dual rail encoding worked into the fabric.

I guess my point is that CMOS is cool, but it would be nice if people
could experiment with other logic styles without giving up the
coolness of programmable hardware. The most straightforward way I can
think of is to give people a pile of pass transistors connected by
programmable interconnect. I'm sure moving to a coarser granularity is
probably a good idea too.

- a

--
"The first time I read this book I felt what I could only explain as a
great disturbance in the Force: it was as if a billion washing
machinces all became unbalanced at once and were suddenly silenced."

-- anonymous book reviewer on Amazon.com

 

[Jim Granville]

Adam Megacz wrote:

Field Programmable Pass Transistor Array.

Is there such a thing? I'm imagining even something that's NMOS-only
with dual rail encoding worked into the fabric.

I guess my point is that CMOS is cool, but it would be nice if people
could experiment with other logic styles without giving up the
coolness of programmable hardware. The most straightforward way I can
think of is to give people a pile of pass transistors connected by
programmable interconnect. I'm sure moving to a coarser granularity is
probably a good idea too.

If you were an IC vendor, how many of these could you expect to sell ?
The answer to that will tell you if there is such a thing.

So what does exist :
There are
* Programmable Cross points, from Lattice
* Programmable Analog parts, but usually with rather 'ordinary'
analog specs, narrow Frequency ranges, and rather high prices.

* Analog Switch technology is widely deployed, and comes in tiny
packages, so you can always construct your own...

* and there is always a sea of CD4007's

-jg

 

[Philip Freidin]

On Wed, 02 Jun 2004 20:40:28 -0700, Adam Megacz <adam@megacz.com> wrote:

Field Programmable Pass Transistor Array.

Is there such a thing? I'm imagining even something that's NMOS-only
with dual rail encoding worked into the fabric.

I guess my point is that CMOS is cool, but it would be nice if people
could experiment with other logic styles without giving up the
coolness of programmable hardware. The most straightforward way I can
think of is to give people a pile of pass transistors connected by
programmable interconnect. I'm sure moving to a coarser granularity is
probably a good idea too.

- a

Two companies have made such parts in the past and offered them to end
users:
Icube: made some fairly large cross bar products. Had limitted
success. Invented the quichswich products, which were
seccond sourced by IDT, and these live on, but are
trivial compared to the crossbar products. The remnants
of the company were acquired by Fairchild.
These parts appear to live on as:

http://www.fairchildsemi.com/pf/OC%2FOCX256P.html
http://www.fairchildsemi.com/ds/OC/OCX256P.pdf

Aptix: This was more of a chip that looked like an FPGA, with
all the logic blocks missing. So you got to route stuff
similar to the way you might route I/O to I/O on an
FPGA. Their target market was the configurable
interconnect between a sea of FPGAs on a board, used for
ASIC emulation. Innitially these cr*zy people did these
chips as anti-fuse. Its lack of success was blamed on
there not being a market for these types of parts. That
one-time programmability might be an issue was apparently
not thought to be a restriction. The company restructured
and eventually did a "RAM" based product, but it also
changed into a systems company, selling boards with
their parts, as well as FPGAs from various vendors. A
major part of their system is the SW that partitions
large designs across multiple FPGAs, and figures out what
goes into the external routing chips.

http://www.aptix.com

The company still seems to be using this technology, see

http://www.aptix.com/products/overview.htm

in the second paragraph:

"Aptix’s proprietary Field Programmable Interconnect (FPIC™)
technology"

Currently, things are less that ideal for this company:

http://www.governmententerprise.com/story/showArticle.jhtml?articleID=20900355

http://www.reed-electronics.com/electronicnews/article/CA414082?industryid=22111&industry=EDA


Philip