FPGA for a Newcomer

[John Bowen]

I've had several courses on Digital Logic, ......but that was in the early
1980s !! I was very familiar with the 7400 series of integrated circuits,
and could name the gates and truth tables off the top of my head. A lot of
years have passed since I worked with these chips, and I've fallen way
behind in technology. But now I'd like to do some experimenting on my own.
I wanted to build something like a simple Annunciator Panel type project,
so I dug out my old logic books to brush up. What I found out was that I
needed about 50-75 Logic Gates for my particular design, though I'm sure I
could pare that down some, but the thought of mounting and wiring (I used
to wire-wrap a lot) about 25 or more Integrated Circuits just kind of
discouraged me. I was asking a fellow Technician about maybe using some sort
of EEProm, and he told me about Field Programmable Gate Arrays...according
to what I've since learned, it looks like I should be able to program a FPGA
with my logic design(or reprogram it if I make a mistake)....my logic would
be a series of And, Nor, etc. gates, Flip Flops, etc, and use contact
closures for inputs and LEDs for outputs. Am I correct in my interpretation
of what a FPGA is, and how it operates?
I was looking at 10 inputs (contact closures) and 10 simple LEDs for the
outputs on this first project. Since I'm not familiar with the pin
assignments for the I/Os, and what's needed to program these FPGAs, would
any of you have a recommendation on what family and size of FPGA I should
start with? Or is an FPGA really what I need? What about a programmer (or
programming method) and software? I'd be most comfortable using a software
that graphically displays my gates and their connections if there is such a
thing, but since this is just going to be a playtoy for now, I guess cost
needs to be a consideration, so inexpensive developmental would be best. Is
there a Complete Experimenter's Kit available for someone with my interests?
Or would I be better off buying individual components to suit my needs?
I've read some of the posts, and it sounds like you guys are WAAAY up on
the curve....can you help me get started?
Thanks, John.

 

[Phil Hays]

John Bowen wrote:

... Am I correct in my interpretation of what a FPGA is, and
how it operates?

Yes.

... a recommendation on what family and size of FPGA I should
start with? Or is an FPGA really what I need?

A very similar product called a CPLD is probably closer to your needs.
CPLDs are smaller, simpler and cheaper. As you don't need the number of
gates even the smallest FPGA has (~10,000) you probably want to look at
CPLDs first.

What about a programmer (or programming method) and software?

Programmer is a cable between a parallel port on a PC and software can
be various free packages from the CPLD vendor. I'd suggest looking at
Altera's MAX and Xilinx's Coolrunner and 9500 stuff. Software is at:

http://www.altera.com/products/software/free/fre-emax_baseline.html
http://www.xilinx.com/xlnx/xil_prodcat_landingpage.jsp?title=ISE+WebPack

Yes, these are just the biggest two vendors. See the vendor list at:

http://www.optimagic.com/

I'd be most comfortable using a software
that graphically displays my gates and their connections if there is such a
thing, but since this is just going to be a playtoy for now, I guess cost
needs to be a consideration, so inexpensive developmental would be best.

Schematic entry packages are included with free software packages from
Altera and Xilinx.

Is
there a Complete Experimenter's Kit available for someone with my interests?

Two choices:

http://www.xilinx.com/xlnx/xil_prodcat_product.jsp?title=design_kit
http://www.altera.com/products/devkits/kit-dev_platforms.jsp

Or would I be better off buying individual components to suit my needs?

Perhaps. Planning on making more than one? Then perhaps making a
circuit board and buying the parts would be a good idea.


--
Phil Hays

 

[Ralph Mason]

"John Bowen" <johnboy@cafes.net> wrote in message
news:3f36447d@news.isdn.net...

I've had several courses on Digital Logic, ......but that was in the early
1980s !! I was very familiar with the 7400 series of integrated circuits,
and could name the gates and truth tables off the top of my head. A lot of
years have passed since I worked with these chips, and I've fallen way
behind in technology. But now I'd like to do some experimenting on my own.
I wanted to build something like a simple Annunciator Panel type
project,
so I dug out my old logic books to brush up. What I found out was that I
needed about 50-75 Logic Gates for my particular design, though I'm sure I
could pare that down some, but the thought of mounting and wiring (I used
to wire-wrap a lot) about 25 or more Integrated Circuits just kind of
discouraged me. I was asking a fellow Technician about maybe using some
sort
of EEProm, and he told me about Field Programmable Gate Arrays...according
to what I've since learned, it looks like I should be able to program a
FPGA
with my logic design(or reprogram it if I make a mistake)....my logic
would
be a series of And, Nor, etc. gates, Flip Flops, etc, and use contact
closures for inputs and LEDs for outputs. Am I correct in my
interpretation
of what a FPGA is, and how it operates?
I was looking at 10 inputs (contact closures) and 10 simple LEDs for
the
outputs on this first project. Since I'm not familiar with the pin
assignments for the I/Os, and what's needed to program these FPGAs, would
any of you have a recommendation on what family and size of FPGA I should
start with? Or is an FPGA really what I need? What about a programmer (or
programming method) and software? I'd be most comfortable using a software
that graphically displays my gates and their connections if there is such
a
thing, but since this is just going to be a playtoy for now, I guess cost
needs to be a consideration, so inexpensive developmental would be best.
Is
there a Complete Experimenter's Kit available for someone with my
interests?
Or would I be better off buying individual components to suit my needs?
I've read some of the posts, and it sounds like you guys are WAAAY up on
the curve....can you help me get started?
Thanks, John.

Have a look at CPLD's

You could probably a $0.99 Xilinx 9532XL to do this. A Jtag programer is
about $10, and the webpack software is free from www.xilinx.com, I think you
can get them in PLCC so with a suitable socket you and wirewrap it.

There are also kits available with the chip on a PCB and a programming
cable.

You can use a schematic layout or a HDL like verilog.

Ralph

 

[Martin Euredjian]

John, have a look at this:
http://www.xilinx.com/publications/products/cpld/logic_handbook.pdf


--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Martin Euredjian

To send private email:
0_0_0_0_@pacbell.net
where
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"John Bowen" <johnboy@cafes.net> wrote in message
news:3f36447d@news.isdn.net...

I've had several courses on Digital Logic, ......but that was in the early
1980s !! I was very familiar with the 7400 series of integrated circuits,
and could name the gates and truth tables off the top of my head. A lot of
years have passed since I worked with these chips, and I've fallen way
behind in technology. But now I'd like to do some experimenting on my own.
I wanted to build something like a simple Annunciator Panel type
project,
so I dug out my old logic books to brush up. What I found out was that I
needed about 50-75 Logic Gates for my particular design, though I'm sure I
could pare that down some, but the thought of mounting and wiring (I used
to wire-wrap a lot) about 25 or more Integrated Circuits just kind of
discouraged me. I was asking a fellow Technician about maybe using some
sort
of EEProm, and he told me about Field Programmable Gate Arrays...according
to what I've since learned, it looks like I should be able to program a
FPGA
with my logic design(or reprogram it if I make a mistake)....my logic
would
be a series of And, Nor, etc. gates, Flip Flops, etc, and use contact
closures for inputs and LEDs for outputs. Am I correct in my
interpretation
of what a FPGA is, and how it operates?
I was looking at 10 inputs (contact closures) and 10 simple LEDs for
the
outputs on this first project. Since I'm not familiar with the pin
assignments for the I/Os, and what's needed to program these FPGAs, would
any of you have a recommendation on what family and size of FPGA I should
start with? Or is an FPGA really what I need? What about a programmer (or
programming method) and software? I'd be most comfortable using a software
that graphically displays my gates and their connections if there is such
a
thing, but since this is just going to be a playtoy for now, I guess cost
needs to be a consideration, so inexpensive developmental would be best.
Is
there a Complete Experimenter's Kit available for someone with my
interests?
Or would I be better off buying individual components to suit my needs?
I've read some of the posts, and it sounds like you guys are WAAAY up on
the curve....can you help me get started?
Thanks, John.