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larwe
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 Posted: Wed Nov 19, 2008 5:59 pm Post subject: FPGA board - Avnet's $39 board? |
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Help? I'm looking for a board like the Avnet "$39 Spartan-3A board"
mentioned all over the web: <http://www.pldesignline.com/products/
207401864>. This board seems to be stamped out of pure unobtanium
sheets but it does seem to be exactly what I want.
I'm looking for something in the $100-ish price range (including a
means to download code, and with free s/w toolchain) that will allow
me to interface to external SRAM so I can implement a tiled video
subsystem and some sprites - a 2D arcade game engine, basically. It
would be convenient if the FPGA had enough room in it for a soft core
(nothing complicated is necessary - something like a fast 8051 would
be fine), but I won't be heartbroken if I have to lash on an external
processor. This is a writing project, so the hardware has to be
available/accessible to impoverished students.
Any thoughts? |
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larwe
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| Posted: Wed Nov 19, 2008 7:35 pm Post subject: Re: FPGA board - Avnet's $39 board? |
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On Nov 19, 1:21 pm, Rich Webb <bbew...@mapson.nozirev.ten> wrote:
| Quote: | This one offers an on-board VGA port as well as a fair amount of SDRAM,
at pretty close to your price point.
http://digilent.us/Products/Detail.cfm?Prod=NEXYS2&Nav1=Products&Nav2...
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Hmm! Digilent's products look to cover my app space better. I'm
deciding if the BASYS is enough... I need to map out the requirements
in a bit more detail.
Thanks for the pointers! Seems I do one of these projects only every
couple of years, so I'm never up to speed with what's available. |
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LittleAlex
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| Posted: Wed Nov 19, 2008 8:21 pm Post subject: Re: FPGA board - Avnet's $39 board? |
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On Nov 19, 9:59 am, larwe <zwsdot...@gmail.com> wrote:
| Quote: | Help? I'm looking for a board like the Avnet "$39 Spartan-3A board"
mentioned all over the web: <http://www.pldesignline.com/products/
207401864>. This board seems to be stamped out of pure unobtanium
sheets but it does seem to be exactly what I want.
Any thoughts?
|
Order it and wait - that's what I did. Even though it was "out of
stock".
In 2~3 weeks it was dropped on my door step. |
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larwe
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| Posted: Wed Nov 19, 2008 11:13 pm Post subject: Re: FPGA board - Avnet's $39 board? |
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On Nov 19, 3:21 pm, LittleAlex <alex.lo...@email.com> wrote:
| Quote: | Help? I'm looking for a board like the Avnet "$39 Spartan-3A board"
Order it and wait - that's what I did. Even though it was "out of
stock".
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How did you order it? The price is $call and it can't be added to a
cart! |
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Rich Webb
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| Posted: Thu Nov 20, 2008 12:21 am Post subject: Re: FPGA board - Avnet's $39 board? |
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On Wed, 19 Nov 2008 09:59:54 -0800 (PST), larwe <zwsdotcom@gmail.com>
wrote:
| Quote: | Help? I'm looking for a board like the Avnet "$39 Spartan-3A board"
mentioned all over the web: <http://www.pldesignline.com/products/
207401864>. This board seems to be stamped out of pure unobtanium
sheets but it does seem to be exactly what I want.
I'm looking for something in the $100-ish price range (including a
means to download code, and with free s/w toolchain) that will allow
me to interface to external SRAM so I can implement a tiled video
subsystem and some sprites - a 2D arcade game engine, basically. It
would be convenient if the FPGA had enough room in it for a soft core
(nothing complicated is necessary - something like a fast 8051 would
be fine), but I won't be heartbroken if I have to lash on an external
processor. This is a writing project, so the hardware has to be
available/accessible to impoverished students.
|
Digilent has a few inexpensive FPGA boards. Once upon a time they also
included a parallel JTAG cable with most of their boards but, with
parallel ports disappearing, they've switched to including on-board
USB-to-JTAG capability on the newer ones. If you have a real parallel
port, they do sell JTAG-3 cables for about US$12.
<http://digilentinc.com/Products/Catalog.cfm?Nav1=Products&Nav2=Programmable&Cat=Programmable%20Logic>
This one offers an on-board VGA port as well as a fair amount of SDRAM,
at pretty close to your price point.
<http://digilent.us/Products/Detail.cfm?Prod=NEXYS2&Nav1=Products&Nav2=Programmable>
Also look at http://www.knjn.com/index.html. They have some interesting
offerings as well.
Both Xilinx and Altera offer free downloadable versions of their tools.
--
Rich Webb Norfolk, VA |
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larwe
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| Posted: Fri Nov 21, 2008 3:40 am Post subject: Re: FPGA board - Avnet's $39 board? |
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On Nov 20, 5:32 pm, Paul Urbanus <urbpub...@hotmail.com> wrote:
[lots of good stuff, snipped].
| Quote: | toward student learning, I would love to work with you on this project.
If you are interested, send an email to moctodscinobrutabru (reverse
this email address, replace the obligitary dot/at, and substitute an 'x'
for the 'cs' at the end of the domain name.
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It's an educational writing project, but I should probably tell you
more about it. (I got your email and will reply a little later...
tomorrow pm maybe).
Really all I /need/ the FPGA (or even a CPLD might do) is to take the
place of a bunch of discrete logic.
The goal is resurrecting an old book idea of mine (originally going to
be titled "The Xilinx Phoenix", and based around the ML403 - but that
board is WAY too expensive and hard to use). I've modified the idea a
bit and am going to try to pimp it to a different publisher - Elsevier
didn't want it, and I'm kind of through with them.
The premise is that in days of yore, parents and grandparents would
carve toys out of wood and bone and elephant tusks and so forth. The
modern equivalent (cyber-Amish folk art) is to make home-made video
games. I'm going to go through various technologies in approximately
chronological order, starting with a pong-style game (a la General
Instruments AY-3-8500) implemented in a small micro. I'm going to go
through progressively more complex homebrew systems and culminate in
an arcade-style system architecture. How far that extends depends on
how dedicated I feel, but I'm aiming for something with a lo-res score
layer, three or four background tile layers for parallax scrolling
effects, and sprites with hardware scaling. In between that I'm going
to have some hardware of the Galaxian ilk, with RGBI graphics only.
These are going to be implemented the way they were implemented in
arcade ASICs - not in software.
Sprite and tile data will be fetched out of "ROM" (either SRAM or
EPROM, but either way, not in the processor's address space).
Since the book presumes the existence of a processor board for the
earlier projects anyway, it's OK to me if I have to strap a CPU to a
CPLD. What I'm trying to avoid is a huge mess of discrete logic, wire-
wrap and other sadomasochism. |
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Paul Urbanus
Guest
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| Posted: Fri Nov 21, 2008 4:32 am Post subject: Re: FPGA board - Avnet's $39 board? |
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Rich Webb wrote:
| Quote: | On Wed, 19 Nov 2008 09:59:54 -0800 (PST), larwe <zwsdotcom@gmail.com
wrote:
Help? I'm looking for a board like the Avnet "$39 Spartan-3A board"
mentioned all over the web: <http://www.pldesignline.com/products/
207401864>. This board seems to be stamped out of pure unobtanium
sheets but it does seem to be exactly what I want.
I'm looking for something in the $100-ish price range (including a
means to download code, and with free s/w toolchain) that will allow
me to interface to external SRAM so I can implement a tiled video
subsystem and some sprites - a 2D arcade game engine, basically. It
would be convenient if the FPGA had enough room in it for a soft core
(nothing complicated is necessary - something like a fast 8051 would
be fine), but I won't be heartbroken if I have to lash on an external
processor. This is a writing project, so the hardware has to be
available/accessible to impoverished students.
Digilent has a few inexpensive FPGA boards. Once upon a time they also
included a parallel JTAG cable with most of their boards but, with
parallel ports disappearing, they've switched to including on-board
USB-to-JTAG capability on the newer ones. If you have a real parallel
port, they do sell JTAG-3 cables for about US$12.
http://digilentinc.com/Products/Catalog.cfm?Nav1=Products&Nav2=Programmable&Cat=Programmable%20Logic
This one offers an on-board VGA port as well as a fair amount of SDRAM,
at pretty close to your price point.
http://digilent.us/Products/Detail.cfm?Prod=NEXYS2&Nav1=Products&Nav2=Programmable
Also look at http://www.knjn.com/index.html. They have some interesting
offerings as well.
Both Xilinx and Altera offer free downloadable versions of their tools.
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For your needs, I highly recommend an older Digilent board, the S3
board, priced at $99 with power supply and download cable. The FPGA on
the board is an XC3S1000, which has more than enough room for an 8051.
Here's a link.
http://www.digilentinc.com/Products/Detail.cfm?Prod=S3BOARD&Nav1=Products&Nav2=Programmable
There was a prior thread on comp.arch.fpga titled, 'Nintendo DS
Screenshots / Video Capture', from which I have copied my reasons for
recommending the S3Board over the S3E board.
*** begin extracted text ***
For a newbie such as yourself (or even an oldie like me) and a project
such as this, I highly recommend the S3 kit over the S3E kit, for a
number of reasons.
1. The expansion connectors on the S3 are standard 0.1 inch pitch
headers, while the S3E board uses a Hirose fine pitch connector for most
of the FPGA I/O. There are some 6-pin 0.1 inch connectors on the 3E
board, but the total number of I/O available on these connectors is a
small fraction of the FPGA I/O. It is much easier for a hobbyist (or
even a professional) to connect stuff to the 0.1 inch headers.
2. The RAM on the S3 board is SRAM, while the S3E board only has DDR2
SDRAM. It is orders of magnitude easier to implement a frame buffer
(which you will need for your project) in SRAM than DDR2 DRAM. The DDR2
requires a controller, while the POSR (Plain Old Static RAM) just
requires you to hook up the address and data lines.
3. The LED display one the S3 board is very easy to use, while the LCD
on the S3E requires more circuitry to initialize and send data to the
display. The only thing you need for the LED display is some matrix
scanning code, which is provided by Xilinx in their demo code (which is
written in VHDL, not verilog). The LED display is very handy for debugging.
4. The S3 board has 8 slide switches and 4 pushbutton switches for
general use, while the S3E board primarily uses a rotary encoder which
needs to be decoded. Switches are also great for debugging and changing
operating modes easily.
*** end extracted text ***
As you can see, the S3Board has externally connected, 256Kbyte x 32 bit,
10 ns, SRAM. There is plenty of bandwidth to easily implement a tiled
(character-based) display system as well as provide code storage for a
CPU. The 10ns random access time for this SRAM is much faster than the
70ns random access time of the cellular RAM used on the NEXSYS2 board.
The BASYS board has no externally connected SRAM, and the 100K gate FPGA
would not be enough gates to include a CPU.
Interesting that you mentioned the 8051 as a processor to include in the
FPGA. In fact, I found an 8052 on opencores.org that also has the 8K
Intel BASIC-52 interpreter ROM code. I have targeted this to the NEXSYS
board, using FPGA blockrams to implement the 8K ROMS to hold the BASIC
and to also implement an additional 4K of RAM for BASIC programs and
stack/variable space for the interpreter. Communication is through a
serial line with autobaud implemented.
As a test, after reading your post I retargeted the 8052 with BASIC ROM
+ 4K RAM to the XC2S200-FT256 FPGA used on the S3BOARD - and it fit!
There are still 6 blockrams (out of 12 unused), but the logic is mostly
full. However, the logic to implement a graphics tiling is almost
nothing - mainly just concatenating some counters and character values
to generate SRAM addresses. I suspect that the sprite processing
hardware will fit also, unless it is really sophisticated.
I also have working VHDL code to implement a bitmapped XGA resolution
(1024 x 768) display using the external SRAM. The input to the SRAM is
via SPI, but could be easily replaced with code to map the frame memory
into a portion of the 8051 address space. Note that bitmapped display
doesn't have any arbitration code at this time - the non-display port
has priority, which causes screen 'hash' when writing to the display.
This would be easy to fix, though.
I'm going to try and add the XGA display controller code to the 8052
code and see if it still fits. I'll let you know how it turns out.
I have a long background with Xilinx FPGAs and several of their eval
kits, as well as experience programming a tiled/sprite-based graphics
system (PARSEC on the long-defunct TI 99/4A). If your effort is directed
toward student learning, I would love to work with you on this project.
If you are interested, send an email to moctodscinobrutabru (reverse
this email address, replace the obligitary dot/at, and substitute an 'x'
for the 'cs' at the end of the domain name. |
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Mark McDougall
Guest
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| Posted: Fri Nov 21, 2008 6:15 am Post subject: Re: FPGA board - Avnet's $39 board? |
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Paul Urbanus wrote:
| Quote: | However, the logic to implement a graphics tiling is almost
nothing - mainly just concatenating some counters and character values
to generate SRAM addresses. I suspect that the sprite processing
hardware will fit also, unless it is really sophisticated.
|
I've written several tilemap & sprite-based modules and the resource
requirements are trivial. On Altera the tilemap logic is 65 cells, whilst
the sprite logic for 8 sprites is 29 cells.
Also, the original impetus for a tilemap/sprite system back in the day was
the minimal RAM requirements - 1 or 2KB of memory is plenty for a usable
display - and using internal dual-port RAM blocks is especially attractive
in this case. Tile and sprite data can be stored in (external) single-port
RAM where no arbitration is required.
| Quote: | I have a long background with Xilinx FPGAs and several of their eval
kits, as well as experience programming a tiled/sprite-based graphics
system (PARSEC on the long-defunct TI 99/4A).
|
Not having a go at you at all Paul, but I noticed...
from <http://www.videogamehouse.net/parsec.html>
"This was the first game to use bit map graphics on the TI-99/4A, which is
one of the reasons for the big leap in graphics quality over many earlier
games."
So... tilemap/sprite system...??? :)
Regards,
--
Mark McDougall, Engineer
Virtual Logic Pty Ltd, <http://www.vl.com.au>
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266 |
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Paul Urbanus
Guest
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| Posted: Fri Nov 21, 2008 9:04 am Post subject: Re: FPGA board - Avnet's $39 board? |
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Mark McDougall wrote:
| Quote: | Paul Urbanus wrote:
However, the logic to implement a graphics tiling is almost
nothing - mainly just concatenating some counters and character values
to generate SRAM addresses. I suspect that the sprite processing
hardware will fit also, unless it is really sophisticated.
I've written several tilemap & sprite-based modules and the resource
requirements are trivial. On Altera the tilemap logic is 65 cells, whilst
the sprite logic for 8 sprites is 29 cells.
Also, the original impetus for a tilemap/sprite system back in the day was
the minimal RAM requirements - 1 or 2KB of memory is plenty for a usable
display - and using internal dual-port RAM blocks is especially attractive
in this case. Tile and sprite data can be stored in (external) single-port
RAM where no arbitration is required.
I have a long background with Xilinx FPGAs and several of their eval
kits, as well as experience programming a tiled/sprite-based graphics
system (PARSEC on the long-defunct TI 99/4A).
Not having a go at you at all Paul, but I noticed...
from <http://www.videogamehouse.net/parsec.html
"This was the first game to use bit map graphics on the TI-99/4A, which is
one of the reasons for the big leap in graphics quality over many earlier
games."
So... tilemap/sprite system...??? :)
Regards,
Actually, Mark, the video chip used in the TI 99/4A, the TMS9918A, was |
fundamentally a tiled/sprite display controller. The 'bitmap II' mode
that was used in Parsec was modified tiled display modes whereby there
were 3 different character set definitions for the upper, middle, and
lower thirds of the screen. And some of the elements for Parsec, such as
the scorekeeping, used the tiled (character) aspect of the display where
the character definitions were not changed. All of the movable objects,
such as player ship, enemy ships, and asteroids, were sprites.
Now, you didn't make your post to sprite me, did you?  |
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mng
Guest
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| Posted: Fri Nov 21, 2008 10:26 pm Post subject: Re: FPGA board - Avnet's $39 board? |
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On Nov 19, 3:13 pm, larwe <zwsdot...@gmail.com> wrote:
| Quote: | On Nov 19, 3:21 pm, LittleAlex <alex.lo...@email.com> wrote:
Help? I'm looking for a board like the Avnet "$39 Spartan-3A board"
Order it and wait - that's what I did. Even though it was "out of
stock".
How did you order it? The price is $call and it can't be added to a
cart!
|
Perhaps they've sold out the next shipment already? Give them a call
to see what's up.
http://groups.google.com/group/avnet-spartan-3a-eval-kit/browse_frm/thread/d17e5b36c12643e0# |
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Scott Gravenhorst
Guest
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| Posted: Sat Nov 22, 2008 9:01 pm Post subject: Re: FPGA board - Avnet's $39 board? |
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On Fri, 21 Nov 2008 14:26:10 -0800 (PST), mng
<michael.jh.ng@gmail.com> wrote:
| Quote: | On Nov 19, 3:13 pm, larwe <zwsdot...@gmail.com> wrote:
On Nov 19, 3:21 pm, LittleAlex <alex.lo...@email.com> wrote:
Help? I'm looking for a board like the Avnet "$39 Spartan-3A board"
Order it and wait - that's what I did. Even though it was "out of
stock".
How did you order it? The price is $call and it can't be added to a
cart!
Perhaps they've sold out the next shipment already? Give them a call
to see what's up.
http://groups.google.com/group/avnet-spartan-3a-eval-kit/browse_frm/thread/d17e5b36c12643e0#
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I have two of these boards. Avnet changes the website to prevent
orders when they run out of boards. These boards turned out to be
much more popular than Avnet expected. The FPGA on it is quite
capable. I put an 8 voice polyphonic MIDI music synthesizer in one. |
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Mark McDougall
Guest
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| Posted: Mon Nov 24, 2008 6:48 am Post subject: Re: FPGA board - Avnet's $39 board? |
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Paul Urbanus wrote:
| Quote: | Now, you didn't make your post to sprite me, did you?
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That was a fu-tile attempt at humour Paul! :P
Regards,
--
Mark McDougall, Engineer
Virtual Logic Pty Ltd, <http://www.vl.com.au>
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266 |
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Mark McDougall
Guest
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| Posted: Mon Nov 24, 2008 6:52 am Post subject: Re: FPGA board - Avnet's $39 board? |
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larwe wrote:
| Quote: | The goal is resurrecting an old book idea of mine (originally going to
be titled "The Xilinx Phoenix", and based around the ML403 - but that
board is WAY too expensive and hard to use). I've modified the idea a
bit and am going to try to pimp it to a different publisher - Elsevier
didn't want it, and I'm kind of through with them.
|
I recall you mentioned this project/book a few years ago. I also answered
at the time that I had a similar idea, although geared more towards a
general 'emulation bible' that covered software and hardware emulation.
Never got around to doing anything about it though...  IMHO I tend to
think the horse has already bolted on that one... every man and his dog is
doing emulation now...
Regards,
--
Mark McDougall, Engineer
Virtual Logic Pty Ltd, <http://www.vl.com.au>
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266 |
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