Altera Triple Speed Ethernet MegaCore Function Manuel d'utilisateur télécharger pdf (Page 172)

Figure 9-1: Triple-Speed Ethernet Timing Constraint Example

user_instance.v

TOP.v

Altera PLL

10/100/1000-Mbps Ethernet MAC

with 1000BASE-X/SGMII

PCS and PMA

(with internal FIFO)

ff_tx_clk

ff_rx_clk

tse_variation.v

ref_clk

clk

ext_clk

pll_inclk

100-Mhz 50-Mhz

110-Mhz

inclk0

c1 c0

xcvr_ref_clk

125-Mhz

Note to Figure 9–2:

1. reconfig_clk is not shown in this example. Constrain reconfig_clk based on your design implemen-

tation.

The example in above consists of the following Verilog modules:

• TOP.v—The top level design module which contains an Altera PLL and a user-defined instance. The top

level input clocks consist of pll_inclk, ext_clk, and xcvr_ref_clk.

• user_instance.v—The user-defined instance that instantiates the Triple-Speed Ethernet MegaCore function.

• tse_variation.v—A Triple-Speed Ethernet MegaCore function variation. This example uses a 10/100/1000-

Mbps Ethernet MAC with an internal FIFO buffer, a 1000BASE-X/SGMII PCS, and an embedded PMA.

The frequency for the PLL clock input, inclk0, is 100 MHz, and the frequency for the PLL clock output, c0,

is 110 MHz. The Triple-Speed Ethernet MAC Avalon-ST clocks, ff_tx_clk and ff_rx_clk, use c0 as the

clock source. The input clock frequency for the transceiver reference clock, xcvr_ref_clk, is 125 MHz.

Example of the Triple-Speed Ethernet MegaCore function timing constraint file:

# PLL clock input, 100 MHz

create_clock -name pll_inclk -period 10.000 [get_ports {pll_inclk}]

# ext_clk, 50 MHz

create_clock -name ext_clk -period 20.000 [get_ports {pll_ext_clk}]

# xcvr_ref_clk, 125 MHz

create_clock -name xcvr_ref_clk -period 8.000 [get_ports {xcvr_ref_clk}]

# Derive PLL generated output clocks.

derive_pll_clocks

Timing Constraints

Altera Corporation

Send Feedback

UG-01008

Creating Clock Constraints

9-2

2014.06.30

1 2 ... 167 168 169 170 171 172 173 174 175 176 177 ... 222 223

Commentaires sur ces manuels

Pas de commentaire

Altera Triple Speed Ethernet MegaCore Function Manuel d'utilisateur Page 172

Commentaires sur ces manuels

Produits connexes et manuels pour Instruments de mesure Altera Triple Speed Ethernet MegaCore Function