different I/O buffers available inXilinx FPGA

could anyone please explain me the difference between the buffers IBUF
OBUF BUFGP BUFGDLL BUFT etc available in XILINX FPGA.

"vlsi_learner" <bajajk@gmail.com> schrieb im Newsbeitrag
news:1113563692.919736.183860@f14g2000cwb.googlegroups.com...
> could anyone please explain me the difference between the buffers IBUF
> OBUF BUFGP BUFGDLL BUFT etc available in XILINX FPGA.
>
RTFM

antti

vlsi_learner wrote:
> could anyone please explain me the difference between the buffers
IBUF
> OBUF BUFGP BUFGDLL BUFT etc available in XILINX FPGA.

Just have a look at
  <Xilinx-Install-Dir>\doc\usenglish\books\docs\lib\lib.pdf

Jochen

Jochen wrote:

> vlsi_learner wrote:
> 
>>could anyone please explain me the difference between the buffers
> 
> IBUF
> 
>>OBUF BUFGP BUFGDLL BUFT etc available in XILINX FPGA.
> 
> 
> Just have a look at
>   <Xilinx-Install-Dir>\doc\usenglish\books\docs\lib\lib.pdf
> 
> Jochen
> 
or...
http://toolbox.xilinx.com/docsan/xilinx6/books/docs/lib/lib.pdf

EG

Engineering Guy wrote:
> or...
> http://toolbox.xilinx.com/docsan/xilinx6/books/docs/lib/lib.pdf
I like this one best:

http://toolbox.xilinx.com/docsan/xilinx5/data/docs/lib/lib0027_11.html

or this for Virtex-4:

http://toolbox.xilinx.com/docsan/xilinx6/books/data/docs/v4lsc/v4lsc0013_4.html

cu,
Sean

thanks a lottt

Hi Antti Lukats,

> "vlsi_learner" <bajajk@gmail.com> schrieb im Newsbeitrag
> news:1113563692.919736.183860@f14g2000cwb.googlegroups.com...
>> could anyone please explain me the difference between the buffers IBUF
>> OBUF BUFGP BUFGDLL BUFT etc available in XILINX FPGA.
>>
> RTFM

Are you having a bad day?

Ben

As others have pointed out, the manual does explain them.  However, 
maybe more of what you are looking for is when to use them.  This is all 
off the top of my head.  My apologies for any minor inaccuracies.

IBUF is the normal input buffer that connects an IOB from an input pin 
to the internal FPGA logic.

IBUFG is the global input buffer.  It is for the same purpose as IBUF 
except one uses it where one is connecting to a DCM or a BUFGMUX.  This 
minimizes the skew of signals coming from off chip.  For example, if 
your crystal is used by the FPGA and other devices on the board one 
would want the clock inside the FPGA to be as close to the clock outside 
the FPGA so that in the end your outputs of the FPGA are as close to the 
same clock edge as possible.  If one is using clock feedback from the 
board IBUFG should also be used.

OBUF is the opposite of the IBUF, connecting internal logic to an IOB 
for output.

BUFG is one use of a BUFGMUX (see the appropriate FPGA user guide) and 
is used to distribute a signal inside the FPGA using the global nets to 
minimize skew inside the FPGA.  BUFGs are generally used for clocks, 
resets, and signals where minimal skew is very important.  If one is 
using a DCM and the output goes to more than one location, one probably 
should use a BUFG.

BUFGP is a IBUFG followed by a BUFG.  A BUFGP is used when one wants to 
distribute a signal across the FPGA with minimal skew and one is not 
using a DCM to do it.

BUFGDLL is an IBUFG driving a CLKDLL.  The CLKDLL is the primitives in 
Spartan II, Spartan IIe, Virtex, and Virtex-e prior to the DCM.

BUFT is a tri-state buffer.  This is used when one needs to implement 
tri-state.

There are other buffers too, like IOBUF for bi-directional and xBUFDS 
for differential.

If you let them, the ISE tools will take care of a lot of this buffering 
for you.  Some thing like tri-state need to be taken care of by the 
user.  EDK takes care of its own buffers if it is a top-level design and 
otherwise provides a stub to the user.

This post is my own opinion, and not an official Xilinx post.  Reverse 
domain and remove the NOSPAM from e-mail address to respond by e-mail.

vlsi_learner wrote:

> could anyone please explain me the difference between the buffers IBUF
> OBUF BUFGP BUFGDLL BUFT etc available in XILINX FPGA.

"Ben Twijnstra" <btwijnstra@gmail.com> schrieb im Newsbeitrag
news:erT7e.63478$Sc7.10321@amsnews05.chello.com...
> Hi Antti Lukats,
>
> > "vlsi_learner" <bajajk@gmail.com> schrieb im Newsbeitrag
> > news:1113563692.919736.183860@f14g2000cwb.googlegroups.com...
> >> could anyone please explain me the difference between the buffers IBUF
> >> OBUF BUFGP BUFGDLL BUFT etc available in XILINX FPGA.
> >>
> > RTFM
>
> Are you having a bad day?
>
> Ben

YES.
I wanted actually to appologizy to the OP, as my comment wasnt justified.
Sorry.

Antti
PS Ben, I will reply to you separatly.

thanks Benjamin.. i got the idea...this was what i was looking for