On 4=A4=EB13=A4=E9, =A4W=A4=C82=AE=C917=A4=C0, "H. Peter Anvin" <h...@zytor=
.com> wrote:
> -jg wrote:
>
> > You need to define just how much theCPLDportion needs to DO.
> > - ie how many macrocells are needed
> > How much memory is shared, and what bandwdith is needed ?
>
> > It is quite easy to set up shared memory access on a Microcontroller,
> > with external RAM and aCPLD-  choose a fast SRAM, and lock the
> >CPLDaccess to the idle periods in the uC bus - that way,
> > you emulate dual-port memory with cheap SRAM.
>
> Yes, I've pretty much independently come to the same conclusion.  This
> is most likely the sanest option.
>
> The next step is to prototype theCPLDcode and see what kind ofCPLDit
> can fit into.
>
> The only potential concern with having theCPLDdo the arbitration of
> the SRAM bus is needing too many I/O pins on theCPLD, but I'm sure that
> can be dealt with, too.
>
>         -hpa

    regards:

          good answer

H. Peter Anvin <hpa@zytor.com> wrote:
...
> The only potential concern with having the CPLD do the arbitration of 
> the SRAM bus is needing too many I/O pins on the CPLD, but I'm sure that 
> can be dealt with, too.

Go with an FPGA. Some more external infrastructure needed, but much
more possibilities...
-- 
Uwe Bonnes                bon@elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------

-jg wrote:
> 
> You need to define just how much the CPLD portion needs to DO.
> - ie how many macrocells are needed
> How much memory is shared, and what bandwdith is needed ?
> 
> It is quite easy to set up shared memory access on a Microcontroller,
> with external RAM and a CPLD -  choose a fast SRAM, and lock the
> CPLD access to the idle periods in the uC bus - that way,
> you emulate dual-port memory with cheap SRAM.
> 

Yes, I've pretty much independently come to the same conclusion.  This 
is most likely the sanest option.

The next step is to prototype the CPLD code and see what kind of CPLD it 
can fit into.

The only potential concern with having the CPLD do the arbitration of 
the SRAM bus is needing too many I/O pins on the CPLD, but I'm sure that 
can be dealt with, too.

	-hpa

On Apr 11, 12:10 pm, "zcsizma...@gmail.com" <zcsizma...@gmail.com>
wrote:
> On Apr 10, 11:51 pm, "H. Peter Anvin" <h...@zytor.com> wrote:
>
>
>
> > zcsizma...@gmail.com wrote:
>
> > > How big is your form factor? I think it is still easier to make a
> > > motherboard for the Virtex-4 Mini module, and add a 5V TTL logic
> > > converter and the power supplies vs. designing a new board.
> > > I wouldn't worry about power supplies. That should be your smallest
> > > problem.
>
> > > Other option is to put a small Spartan II and a uC (with external data
> > > bus support, e.g. Atmega), and use the dual-port ram inside Spartan to
> > > share memory between uC and Spartan.
>
> > The form factor is quite big -- 100x160 mm (Eurocard), so space is
> > largely plentiful.  The Virtex-4 mini module is quite expensive, though
> > ($250), which is okay for a one-off but may be too much for an actual
> > production run -- I would have to do the math on that.
>
> > I didn't realize that Spartan II was 5 V tolerant.  I'm going to have to
> > see if that is practical to combine with a microcontroller.  Still needs
> > dual power supplies, though   If not, a 200,000-gate Spartan II
> > apparently retails for $26 these days; that FPGA should be large enough
> > to fit an 8- or 16-bit microcontroller core plus all the logic.
>
> > Anyone has any kind of idea how long Spartan II is likely to remain on
> > the market?
>
> >         -hpa
>
> IIRC you can put a simple microblaze (32 bits) design into the Spartan-
> II, IF you don't need too much code space. But picoblaze (8 bit) can
> be done as well.
> Probably that would be the easiest solution, have a block ram in your
> FPGA logic, and map that RAM into uBlaze.


A suggestion if you decide to go 8-bit with PicoBlaze.  Nial Stewart
has
adapted the Picoblaze 2 (Virtex-2 version) for Spartan 2.  This
overcomes
the extremely small (256 instruction) code space of the original
PicoBlaze
for Spartan 2.  I have used this in the Spartan 2 200K gate part and
it
leaves most of the logic free for your other needs.

HTH,
Gabor

PS here's the header from the Nial's perl script for converting
instruction
RAM from Virtex 2 to Spartan format:

# This is a Perl utility written to convert initialisation
# definitions from Virtex Blockram (1024 x 18 bits) to SpartanII
# Blockram (5 * 256 x 4 bits) format.
#
# This is to allow the bigger version of the Picoblaze processor
# to be used with SpartanII devices.
#
# This is provided as is for general use without any guarantees or
# warranties.
#
# =A9 Nial Stewart Developments 2003
# www.nialstewartdevelopments.co.uk

"H. Peter Anvin" <hpa@zytor.com> wrote in message 
news:1cKdnUK2McvPnIHbnZ2dnUVZ_sOknZ2d@comcast.com...
> Hi all,
>
> I have a potential (hobby) project, where I'm looking at needing, in 
> effect, a CPLD and a &#4294967295;C that can share memory.  +5 V I/O tolerance is 
> necessary (for about 52 signals coming into the board), and I would like 
> to keep the power supply complexity to a minimum since I'm really a 
> software guy and don't particularly trust my board layout skills.
>
> Anyway, I was looking at using an Atmel FPSLIC part, but it looks like the 
> tools are prohibitively expensive.  I was wondering if anyone knows of a 
> similar part that would be less expensive once the tools are accounted 
> for?  The alternatives seem to be using a Cyclone or Spartan big enough to 
> integrate the whole design including &#4294967295;C, but they require complex power 
> supplies and external voltage converters, or cobble something together 
> from multiple parts.
>
http://www.enterpoint.co.uk/component_replacements/craignell.html
Cheers, Syms R. Brewer. 

H=2E Peter Anvin wrote:
> Hi all,
>
> I have a potential (hobby) project, where I'm looking at needing, in
> effect, a CPLD and a =B5C that can share memory.  +5 V I/O tolerance is
> necessary (for about 52 signals coming into the board), and I would like
> to keep the power supply complexity to a minimum since I'm really a
> software guy and don't particularly trust my board layout skills.
>
> Anyway, I was looking at using an Atmel FPSLIC part, but it looks like
> the tools are prohibitively expensive.  I was wondering if anyone knows
> of a similar part that would be less expensive once the tools are
> accounted for?  The alternatives seem to be using a Cyclone or Spartan
> big enough to integrate the whole design including =B5C, but they require
> complex power supplies and external voltage converters, or cobble
> something together from multiple parts.

You need to define just how much the CPLD portion needs to DO.
- ie how many macrocells are needed
How much memory is shared, and what bandwdith is needed ?

It is quite easy to set up shared memory access on a Microcontroller,
with
external RAM and a CPLD -  choose a fast SRAM, and lock the
CPLD access to the idle periods in the uC bus - that way,
you emulate dual-port memory with cheap SRAM.

If the uC memory bandwidth are lower than the CPLD-memory, you could
consider a SPI port into the CPLD, as that simplifies the PCB layout
and opens more uC options.
-jg

On Apr 10, 11:51 pm, "H. Peter Anvin" <h...@zytor.com> wrote:
> zcsizma...@gmail.com wrote:
>
> > How big is your form factor? I think it is still easier to make a
> > motherboard for the Virtex-4 Mini module, and add a 5V TTL logic
> > converter and the power supplies vs. designing a new board.
> > I wouldn't worry about power supplies. That should be your smallest
> > problem.
>
> > Other option is to put a small Spartan II and a uC (with external data
> > bus support, e.g. Atmega), and use the dual-port ram inside Spartan to
> > share memory between uC and Spartan.
>
> The form factor is quite big -- 100x160 mm (Eurocard), so space is
> largely plentiful.  The Virtex-4 mini module is quite expensive, though
> ($250), which is okay for a one-off but may be too much for an actual
> production run -- I would have to do the math on that.
>
> I didn't realize that Spartan II was 5 V tolerant.  I'm going to have to
> see if that is practical to combine with a microcontroller.  Still needs
> dual power supplies, though   If not, a 200,000-gate Spartan II
> apparently retails for $26 these days; that FPGA should be large enough
> to fit an 8- or 16-bit microcontroller core plus all the logic.
>
> Anyone has any kind of idea how long Spartan II is likely to remain on
> the market?
>
>         -hpa

IIRC you can put a simple microblaze (32 bits) design into the Spartan-
II, IF you don't need too much code space. But picoblaze (8 bit) can
be done as well.
Probably that would be the easiest solution, have a block ram in your
FPGA logic, and map that RAM into uBlaze.

zcsizmadia@gmail.com wrote:
> 
> How big is your form factor? I think it is still easier to make a
> motherboard for the Virtex-4 Mini module, and add a 5V TTL logic
> converter and the power supplies vs. designing a new board.
> I wouldn't worry about power supplies. That should be your smallest
> problem.
> 
> Other option is to put a small Spartan II and a uC (with external data
> bus support, e.g. Atmega), and use the dual-port ram inside Spartan to
> share memory between uC and Spartan.
> 

The form factor is quite big -- 100x160 mm (Eurocard), so space is 
largely plentiful.  The Virtex-4 mini module is quite expensive, though 
($250), which is okay for a one-off but may be too much for an actual 
production run -- I would have to do the math on that.

I didn't realize that Spartan II was 5 V tolerant.  I'm going to have to 
see if that is practical to combine with a microcontroller.  Still needs 
dual power supplies, though   If not, a 200,000-gate Spartan II 
apparently retails for $26 these days; that FPGA should be large enough 
to fit an 8- or 16-bit microcontroller core plus all the logic.

Anyone has any kind of idea how long Spartan II is likely to remain on 
the market?

	-hpa

On Apr 10, 6:32 pm, "H. Peter Anvin" <h...@zytor.com> wrote:
> zcsizma...@gmail.com wrote:
>
> > Buy an evaluation board/development kit, probably that's the cheapest,
> > and least effort. Some Xilinx options:
>
> Not an option, I'm afraid (otherwise it would by far be the easiest.)
> Unfortunately, the board needs to fit into a legacy system, which means
> a specific form factor, connector, and power supply (and the need to
> interface to 5 V TTL logic -- I think the system is actually old enough
> that it's real LSTTL buffers on the other side, not HCMOS.)
>
>         -hpa

How big is your form factor? I think it is still easier to make a
motherboard for the Virtex-4 Mini module, and add a 5V TTL logic
converter and the power supplies vs. designing a new board.
I wouldn't worry about power supplies. That should be your smallest
problem.

Other option is to put a small Spartan II and a uC (with external data
bus support, e.g. Atmega), and use the dual-port ram inside Spartan to
share memory between uC and Spartan.

zcsizmadia@gmail.com wrote:
> 
> Buy an evaluation board/development kit, probably that's the cheapest,
> and least effort. Some Xilinx options:
> 

Not an option, I'm afraid (otherwise it would by far be the easiest.) 
Unfortunately, the board needs to fit into a legacy system, which means 
a specific form factor, connector, and power supply (and the need to 
interface to 5 V TTL logic -- I think the system is actually old enough 
that it's real LSTTL buffers on the other side, not HCMOS.)

	-hpa