Sign in

username:

password:



Not a member?

Search fpga-cpu



Search tips

Subscribe to fpga-cpu



fpga-cpu by Keywords

Altera | CISCifying | IDE | ISA | Java | JHDL | JTAG | LBU | MicroBlaze | PAR | PCI | RISC | SoC | Spartan | Transputers | Verilog | VHDL | Virtex | VLIW | WebPack | Xilinx | Xsoc | YARD-1A

Ads

Discussion Groups

Discussion Groups | FPGA-CPU | Re: why FPGA?

This list is for discussion of the design and implementation of field-programmable gate array based processors and integrated systems. It is also for discussion and community support of the XSOC Project (see http://www.fpgacpu.org/xsoc).

Re: Re: why FPGA? - Jeff Brower - Jan 11 11:15:00 2005

Rick-

> What? You can drive a shared bus using a 220 ohm series resistor?
> That would give you horrible rise/fall times. I guess if you are
> clocking a one-wire interface that would not be an issue. But any
> normal high speed bus will likely not work with that sort of a driver
> impedance.
>
> Or am I missing something here?

Here is a Xilinx link that talks about it.

http://www.xilinx.com/xlnx/xil_ans_display.jsp?getPagePath=19146&BV_SessionID=@@@@1510964590.1105408727@@@@&BV_EngineID=ccceadddhmijiimcflgcefldfhndfmo.0

They do not mention PCI specifically. I will ask them about it.

-Jeff


(You need to be a member of fpga-cpu -- send a blank email to fpga-cpu-subscribe@yahoogroups.com )


Re: why FPGA? - Author Unknown - Jan 11 17:20:00 2005


--- In , Jeff Brower <jbrower@s...> wrote:
> Rick-
>
> > What? You can drive a shared bus using a 220 ohm series resistor?
> > That would give you horrible rise/fall times. I guess if you are
> > clocking a one-wire interface that would not be an issue. But any
> > normal high speed bus will likely not work with that sort of a driver
> > impedance.
> >
> > Or am I missing something here?
>
> Here is a Xilinx link that talks about it. http://www.xilinx.com/xlnx/xil_ans_display.jsp?getPagePath=19146&BV_SessionID=@@@@1510964590.1105408727@@@@&BV_EngineID=ccceadddhmijiimcflgcefldfhndfmo.0
>
> They do not mention PCI specifically. I will ask them about it.

We are not communicating. The Xilinx app note only talks about how to
protect the Spartan 3 part. It does not address how well the signal
can be driven by the Spartan 3 part through the resistor.





(You need to be a member of fpga-cpu -- send a blank email to fpga-cpu-subscribe@yahoogroups.com )