两个 PCI CHIP 放在同一张 PCI 版卡上运行

allcert06 · 发表于 2005-5-20 14:50:25

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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 · 发表于 2005-5-28 09:37:05

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 · 发表于 2005-7-22 13:16:31

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 · 发表于 2005-7-22 13:21:47

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!