Altera IP Compiler for PCI Express Manuel d'utilisateur Page 107

  • Télécharger
  • Ajouter à mon manuel
  • Imprimer
  • Page
    / 372
  • Table des matières
  • MARQUE LIVRES
  • Noté. / 5. Basé sur avis des utilisateurs
Vue de la page 106
Chapter 5: IP Core Interfaces 5–21
Avalon-ST Interface
August 2014 Altera Corporation IP Compiler for PCI Express User Guide
Figure 5–24 illustrates the timing of the Avalon-ST TX interface. The core can deassert
tx_st_ready
<n>
to throttle the application which is the source.
Figure 5–25 illustrates the timing of the 64-bit TX interface when the IP Compiler for
PCI Express backpressures the application by deasserting
tx_st_ready
. Because the
readyLatency
is two cycles, the application deasserts
tx_st_valid
after two cycles
and holds
tx_st_data
until two cycles after
tx_st_ready
is asserted.
Figure 5–24. Avalon-ST TX Interface Timing
Notes to Figure 5–24:
(1) The maximum allowed response time is 3 clock cycles for the soft IP implementation and 2 clock cycles for the hard IP implementation.
clk
tx_st_ready
tx_st_valid
tx_st_data0[63:0]
tx_st_sop
tx_st_eop
response_time
cycle 1 cycle 2 cycle 3 cycle 4 cycle n
. . .
12345678 910111213
Figure 5–25. 64-Bit Transaction Layer Backpressures the Application
coreclkout
tx_st_sop
tx_st_eop
tx_st_ready
tx_st_valid
tx_st_err
tx_st_data[63:0]
.. . . . . . . . . . .
readyLatency
00. . 00 ... BB... BB ... BBBB0306BBB0305 BB... BB.. BB ... BB ... BB ... BB ... BB....
Vue de la page 106
1 2 ... 102 103 104 105 106 107 108 109 110 111 112 ... 371 372

Commentaires sur ces manuels

Pas de commentaire