> Hi,
>
> Can someone please point me in the right direction.
>
> I attempted to define my LVDS inputs via the UCF file for my Xilinx
> spartan xc3s1500.
>
> NET data_in LOC = F19 | IOSTANDARD = LVDS_25 ;
>
> the Xilinx answer record impies that this will work OK.
>
> http://www.xilinx.com/xlnx/xil_ans_display.jsp?getPagePath=8187
>
> Unfortunately I get the following warning, and the input is set to a
> standard LVCMOS25.
>
> WARNING:Pack:946 - The I/O component data_in has an illegal I/O
> standard value. Components of type IOB do not support I/O standard
> LVDS_25.
> Please correct the IOSTANDARD property value.
>
> I am using ISE 8.2 (Release 8.2.03i Map I.34)
>
> Any ideas what I am doing wrong? Do I need to istantiate the I/O
> buffers?
>
> Thanks for any input,
>
> Steven
Thanks for all the responses.
I instantiated the buffers directly in the HDL with no problems.
I know that the S/W is "free", but I don't know why the documentation
implies that you can just specify the buffers in the UCF (I had the
same issue with BUFG's).
Anyway, thanks again,
Steven
Reply by John Retta●August 8, 20072007-08-08
defparam buf_100.IOSTANDARD = "LVPECL_25";
defparam buf_103.IOSTANDARD = "LVPECL_25";
IBUFDS buf_100 (.I(pad_dsp_adc_fsync_cmd_p), .IB
(pad_dsp_adc_fsync_cmd_n), .O(dsp_adc_fsync_cmd) );
OBUFDS buf_103 (.I(adc_dsp_sdo_q_p), .O(pad_adc_dsp_sdo_p),
.OB(pad_adc_dsp_sdo_n) );
Always check the following doc file for good reference to primitives :
/Xilinx/doc/useglish/books/lib/lib.pdf
--
Regards,
John Retta
Owner and Designer
Retta Technical Consulting Inc.
Colorado Based Xilinx Consultant
email : jretta@rtc-inc.com
web : www.rtc-inc.com
<moogyd@yahoo.co.uk> wrote in message
news:1186593169.119748.316150@q75g2000hsh.googlegroups.com...
> Hi,
>
> Can someone please point me in the right direction.
>
> I attempted to define my LVDS inputs via the UCF file for my Xilinx
> spartan xc3s1500.
>
> NET data_in LOC = F19 | IOSTANDARD = LVDS_25 ;
>
> the Xilinx answer record impies that this will work OK.
>
> http://www.xilinx.com/xlnx/xil_ans_display.jsp?getPagePath=8187
>
> Unfortunately I get the following warning, and the input is set to a
> standard LVCMOS25.
>
> WARNING:Pack:946 - The I/O component data_in has an illegal I/O
> standard value. Components of type IOB do not support I/O standard
> LVDS_25.
> Please correct the IOSTANDARD property value.
>
> I am using ISE 8.2 (Release 8.2.03i Map I.34)
>
> Any ideas what I am doing wrong? Do I need to istantiate the I/O
> buffers?
>
> Thanks for any input,
>
> Steven
>
Reply by John_H●August 8, 20072007-08-08
Do you realize that the LVDS *is* a differential signals and requires two
pins to be defined in the design file?
<moogyd@yahoo.co.uk> wrote in message
news:1186593169.119748.316150@q75g2000hsh.googlegroups.com...
> Hi,
>
> Can someone please point me in the right direction.
>
> I attempted to define my LVDS inputs via the UCF file for my Xilinx
> spartan xc3s1500.
>
> NET data_in LOC = F19 | IOSTANDARD = LVDS_25 ;
>
> the Xilinx answer record impies that this will work OK.
>
> http://www.xilinx.com/xlnx/xil_ans_display.jsp?getPagePath=8187
>
> Unfortunately I get the following warning, and the input is set to a
> standard LVCMOS25.
>
> WARNING:Pack:946 - The I/O component data_in has an illegal I/O
> standard value. Components of type IOB do not support I/O standard
> LVDS_25.
> Please correct the IOSTANDARD property value.
>
> I am using ISE 8.2 (Release 8.2.03i Map I.34)
>
> Any ideas what I am doing wrong? Do I need to istantiate the I/O
> buffers?
>
> Thanks for any input,
>
> Steven
Reply by Symon●August 8, 20072007-08-08
<moogyd@yahoo.co.uk> wrote in message
news:1186593169.119748.316150@q75g2000hsh.googlegroups.com...
> Hi,
> I attempted to define my LVDS inputs via the UCF file for my Xilinx
> spartan xc3s1500.
>
> NET data_in LOC = F19 | IOSTANDARD = LVDS_25 ;
>
>
> WARNING:Pack:946 - The I/O component data_in has an illegal I/O
> standard value. Components of type IOB do not support I/O standard
> LVDS_25.
> Please correct the IOSTANDARD property value.
>
Hi Steven,
I usually instantiate the IBUFDS (see libraries guide) in my HDL and go from
there. Don't forget your terminations...
INST "LVDS_P" DIFF_TERM = TRUE;
INST "LVDS_N" DIFF_TERM = TRUE;
Also, the tools sometimes get their knickers in a twist about 3.3V and 2.5V
banks. Googling should solve that for you.
HTH., Syms.
Reply by ●August 8, 20072007-08-08
Hi,
Can someone please point me in the right direction.
I attempted to define my LVDS inputs via the UCF file for my Xilinx
spartan xc3s1500.
NET data_in LOC = F19 | IOSTANDARD = LVDS_25 ;
the Xilinx answer record impies that this will work OK.
http://www.xilinx.com/xlnx/xil_ans_display.jsp?getPagePath=8187
Unfortunately I get the following warning, and the input is set to a
standard LVCMOS25.
WARNING:Pack:946 - The I/O component data_in has an illegal I/O
standard value. Components of type IOB do not support I/O standard
LVDS_25.
Please correct the IOSTANDARD property value.
I am using ISE 8.2 (Release 8.2.03i Map I.34)
Any ideas what I am doing wrong? Do I need to istantiate the I/O
buffers?
Thanks for any input,
Steven