"Matt Cohen" <matthewlawrencecohen@yahoo.com> wrote in message
news:81fdc5f7.0405251148.23def225@posting.google.com...
> Hi,
> I've done a bunch of work with FPGAs in courses that I took, but in
> all those cases I was using either Xilinx's FPGA demoboards or an
> Altera board designed by my university.  For my lab now I'm designing
> a board that will have a Xilinx CPLD on it, and not much else.  I'm
> sort of the token EE in my lab, and having just gotten my bachelor's
> last year, I've never really designed a board.  My main question
> now...I want to be able to easily reprogram the CPLD, so to access the
> JTAG interface I could just put some header pins on the board and wire
> them up to the right device pins, correct?  Also, it seems to me like
> the board would have to be powered up, i.e. plugged into the back
> plane, to be programmed.  This might not be so convenient as the
> electronics box it will be going in is pretty far away from the PC
> that the design is being on.  Am i mistaken in that the board needs to
> be powered up, or can the cable supply the power?  I guess a solution
> would be to add another header to connect to a separate, portable,
> 3.3V power supply. Thanks,

Most programming adaptors for CPLDs and FPGAs, like those from Altera and
Xilinx, get their power from the target board, so you will need a separate
supply to your board. Just wire the header up to the pins on the device.

Leon

Hi,
I've done a bunch of work with FPGAs in courses that I took, but in
all those cases I was using either Xilinx's FPGA demoboards or an
Altera board designed by my university.  For my lab now I'm designing
a board that will have a Xilinx CPLD on it, and not much else.  I'm
sort of the token EE in my lab, and having just gotten my bachelor's
last year, I've never really designed a board.  My main question
now...I want to be able to easily reprogram the CPLD, so to access the
JTAG interface I could just put some header pins on the board and wire
them up to the right device pins, correct?  Also, it seems to me like
the board would have to be powered up, i.e. plugged into the back
plane, to be programmed.  This might not be so convenient as the
electronics box it will be going in is pretty far away from the PC
that the design is being on.  Am i mistaken in that the board needs to
be powered up, or can the cable supply the power?  I guess a solution
would be to add another header to connect to a separate, portable,
3.3V power supply. Thanks,
Matt Cohen