FP <FPGA.unknown@gmail.com> writes:

> I am looking for a SDRAM controller for Xilinx Spartan3 device in
> Verilog. xapp 134 has one which targets virtex 2 devices. Xilinx MIG
> can be used for DDR and DDR2 SDRAMs. Can a DDR SDRAM controller be
> used to drive SDR SDRAM?
> What other options do I have?

Write one? Assuming you have relatively modest performance
requirements (which seems reasonabnle, or you'd be using DDR), it's
not a huge task. My first significant piece of VHDl was an SDRAM
controller, years ago using a FLEX10KE part!

SDR is really not that complicated, and the timing is fairly easy for
modern devices to handle.  

Cheers,
Martin

-- 
martin.j.thompson@trw.com 
TRW Conekt - Consultancy in Engineering, Knowledge and Technology
http://www.conekt.net/electronics.html

FP wrote:
> Can a DDR SDRAM controller be used to drive SDR SDRAM?

No, unless it is a combined DDR/SDR controller, and those aren't common.
> What other options do I have?

An SDR DRAM controller.

> I am looking for a SDRAM controller for Xilinx Spartan3 device in
> Verilog. xapp 134 has one which targets virtex 2 devices. Xilinx MIG
> can be used for DDR and DDR2 SDRAMs. Can a DDR SDRAM controller be
> used to drive SDR SDRAM?
> What other options do I have?

	I need this SDRAM controller too.
	There are some on OpenCores, but with gotchas.

FP <FPGA.unknown@gmail.com> wrote:

>I am looking for a SDRAM controller for Xilinx Spartan3 device in
>Verilog. xapp 134 has one which targets virtex 2 devices. Xilinx MIG
>can be used for DDR and DDR2 SDRAMs. Can a DDR SDRAM controller be
>used to drive SDR SDRAM?

Yes, with some minor modifications this should be possible. But
beware, there are no usefull free DDR controllers available for the
Spartan3 series.

-- 
Programmeren in Almere?
E-mail naar nico@nctdevpuntnl (punt=.)

I am looking for a SDRAM controller for Xilinx Spartan3 device in
Verilog. xapp 134 has one which targets virtex 2 devices. Xilinx MIG
can be used for DDR and DDR2 SDRAMs. Can a DDR SDRAM controller be
used to drive SDR SDRAM?
What other options do I have?