Xilinx LOGICORE UG144 Manuel d'utilisateur Page 100

  • Télécharger
  • Ajouter à mon manuel
  • Imprimer
  • Page
    / 138
  • Table des matières
  • MARQUE LIVRES
  • Noté. / 5. Basé sur avis des utilisateurs
Vue de la page 99
100 www.xilinx.com 1-Gigabit Ethernet MAC v8.5 User Guide
UG144 April 24, 2009
Chapter 9: Constraining the Core
R
-- DISCONTINUED PRODUCT --
Data Sheet report:
-----------------
All values displayed in nanoseconds (ns)
Setup/Hold to clock gmii_rx_clk
------------+------------+------------+------------------+--------+
| Setup to | Hold to | | Clock |
Source | clk (edge) | clk (edge) |Internal Clock(s) | Phase |
------------+------------+------------+------------------+--------+
gmii_rx_dv | 1.955(R)| -0.017(R)| gmii_rx_clk_bufg | 0.000|
gmii_rx_er | 1.962(R)| -0.031(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<0>| 1.949(R)| -0.013(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<1>| 1.944(R)| -0.009(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<2>| 1.947(R)| -0.012(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<3>| 1.942(R)| -0.008(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<4>| 1.950(R)| -0.015(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<5>| 1.962(R)| -0.026(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<6>| 1.957(R)| -0.022(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<7>| 1.952(R)| -0.020(R)| gmii_rx_clk_bufg | 0.000|
------------+------------+------------+------------------+--------+
Virtex-5 Devices with Delayed Clock
Setup and Hold results for the GMII input bus can be found in the data sheet section of the
Timing Report. However, depending on how the setup/hold requirements have been met,
it may not be immediately obvious how the results relate to Figure 9-1. The following is an
example for the GMII report from a Virtex-5 device where the clock has been delayed to
meet the setup/hold requirements.
Data Sheet report:
-----------------
All values displayed in nanoseconds (ns)
Setup/Hold to clock gmii_rx_clk
------------+------------+------------+------------------+--------+
| Setup to | Hold to | | Clock |
Source | clk (edge) | clk (edge) |Internal Clock(s) | Phase |
------------+------------+------------+------------------+--------+
gmii_rx_dv | -6.198(R)| 7.526(R)| gmii_rx_clk_bufg | 0.000|
gmii_rx_er | -6.225(R)| 7.554(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<0> | -6.149(R)| 7.484(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<1> | -6.152(R)| 7.486(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<2> | -6.206(R)| 7.532(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<3> | -6.207(R)| 7.533(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<4> | -6.134(R)| 7.476(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<5> | -6.134(R)| 7.476(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<6> | -6.170(R)| 7.506(R)| gmii_rx_clk_bufg | 0.000|
gmii_rxd<7> | -6.170(R)| 7.506(R)| gmii_rx_clk_bufg | 0.000|
------------+------------+------------+------------------+--------+
The implementation requires -6.134 ns of setup. Figure 9-2 illustrates that this represents a
figure of 1.866 ns relative to the following rising edge of the clock (since the IDELAY has
acted to delay the clock by an entire period when measured from the input flip-flop). This
is less than the 2 ns required, so there is slack.
Vue de la page 99
1 2 ... 95 96 97 98 99 100 101 102 103 104 105 ... 137 138

Commentaires sur ces manuels

Pas de commentaire