两个 PCI CHIP 放在同一张 PCI 版卡上 运行

allcert06

请问各位大侠
如何将两个PCI CHIP 放置同一张PCI 版卡上
例如:一张PCI 版卡上运行 1394 和 USB 蕊片
  
  是只要控制req 和 gnt线 即可  或是 需要其他方式 使用FPGA 完成
感谢!!

liuiang

你直接用桥就可以啦，，21152，21150都可以，，pci－pci的，，
如果你要用fpga实现的，，要在里面做桥逻辑。。

jingli888ca

Hello, I think you have to do some extra work. The reason is arbitration. From the arbiter's view, it only sees ONE set of REQ# and GNT#. When one of the chips asserts REQ#, the arbiter can NOT tell which devides on this slot assert this signal.
From the chips' view, when both of them see the GNT# assertion, they will compete for the bus.

jingli888ca

Another issue:
When the CPU wants to config each of the chip behind this slot, it can NOT tell which is which because IDSEL# is physically tied to one of the AD# lines. i.e., the slot has already tied ONE AD pin to IDSEL, making it impossible to configure TWO devices.
Without a base address, these two devices can NOT be accessed by any other devices on the PCI bus, even these two chips themsevle can NOT talk to each other.
Your idea will NOT work!