[pci] about bus conflict

[sumnow <sumnow@263.sina.com>]

when I do post simulation for my own pci bridge which uses Blue Beaver's pci model, I get warning information as "bus conflict". I check the code and find out that it is due to the code as following:

  assign #`PAD_MIN_DATA_DLY pci_ad_out_dly1[PCI_BUS_DATA_RANGE:0] = pci_ad_out[PCI_BUS_DATA_RANGE:0];
  assign #`PAD_MAX_DATA_DLY pci_ad_out_dly2[PCI_BUS_DATA_RANGE:0] = pci_ad_out[PCI_BUS_DATA_RANGE:0];
  wire    pci_ad_oe;
  wire    pci_ad_oe_dly1, pci_ad_oe_dly2;
  assign #`PAD_MIN_OE_DLY pci_ad_oe_dly1 = pci_ad_oe;
  assign #`PAD_MAX_OE_DLY pci_ad_oe_dly2 = pci_ad_oe;
  wire    force_ad_x = (pci_ad_oe_dly1 !== pci_ad_oe_dly2)
                     | (pci_ad_oe & (pci_ad_out_dly1 !== pci_ad_out_dly2));
  assign  pci_ext_ad[PCI_BUS_DATA_RANGE:0] = force_ad_x ? `PCI_BUS_DATA_X
                           : (pci_ad_oe_dly2
                           ? pci_ad_out_dly2[PCI_BUS_DATA_RANGE:0]
                           : `PCI_BUS_DATA_Z);

since PAD_MIN_DLY is not equal PAD_MAX_DLY, there is bus conflict near the posedge of clock.

so i am just wondering why add PAD_MIN_DLY and PAD_MAX_DLY for signals. can I define same value for PAD_MIN_DLY and PAD_MAX_DLY to remove the "bus conflict" warning?

Regards

sumnow



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