From: Yu Wang ([email protected])
Date: Wed Apr 05 2000 - 21:09:46 PDT
I'm not sure if it will be helpful to your case.
whatever you can try. I heard about a delay reset chip
from TI or Maxim(should be one of them, I can check it
later). It generates a delayed reset pulse(the delay
is a big amount of time) after power on.
--- Andy Peters <[email protected]> wrote:
> Thanks to all who've responded. Here's what I
> intend to do. I found a TI
> part (CDCF2509) with built-in source terminations
> and nine outputs. The
> oscillator will feed the reference input. The five
> "1Y" outputs will feed
> an FPGA and its four SDRAMs (two of the SDRAMs are
> on top of the board, the
> other two are on the bottom). One of the "2Y"
> outputs will feed a third
> FPGA's clock input. A second "2Y" output will feed
> a second CDCF2509. The
> five "1Y" outputs of the second PLL buffer will feed
> the second FPGA and its
> four SDRAMs. The "2Y" outputs of the second PLL
> buffer will be disabled.
> The board has a clocks-only layer, so we don't think
> we'll have too much
> trouble trying to keep the clock line lengths all
> The only "gotcha" here is that the VME interface
> control chip, a Cypress
> (@#$%!) part, requires an 80 MHz clock, but that
> part has a built-in
> power-on reset circuit that enables it to configure
> itself. That
> configuration fails if the clock is not running, and
> the ~1 ms PLL buffer
> startup time is too long. It seems as if the only
> solution is to run two
> traces from the oscillator - one to the first buffer
> and the second to the
> VME chip. I don't think it's a problem keeping
> those traces equally short,
> and the oscillator data sheet says it can drive +/-
> Again, much thanks to the gurus.
> Andy Peters
> Sr Electrical Engineer
> National Optical Astronomy Observatories
> 950 N Cherry Ave
> Tucson, AZ 85719
> 520 318 8191
> [email protected]
> "Money is property; it is not speech."
> -- Justice John Paul Stevens
> **** To unsubscribe from si-list or si-list-digest:
> send e-mail to [email protected] In the
> BODY of message put: UNSUBSCRIBE si-list or
> UNSUBSCRIBE si-list-digest, for more help, put HELP.
> si-list archives are accessible at
Yu Wang, Ph.D
U.T. MD Anderson Cancer Center
1100 Holcombe Blvd., Box 217
Houston, TX, 77030
Do You Yahoo!?
Talk to your friends online with Yahoo! Messenger.
**** To unsubscribe from si-list or si-list-digest: send e-mail to [email protected] In the BODY of message put: UNSUBSCRIBE si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP.
si-list archives are accessible at http://www.qsl.net/wb6tpu
This archive was generated by hypermail 2b29 : Thu Apr 20 2000 - 11:36:04 PDT