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- Two pci masters connected via pci bridge
March 23, 2006, 9:39 am
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I have a question about pci bridge.
-TMS320C6416 DSP has a HPI/PCI bus .I want to connect two DSPs via
pci on a board which has no pci host ,also there isn't another board
which can serve as a pci host and access the DSPs through a pci bridge.
May I use a pci bridge for local connection of two DSPs without
connecting the host side of pci bridge anywhere (configuring pci bridge
Re: Two pci masters connected via pci bridge
/ / \ \
REQ/Grant / / \ \ REQ/Grant signals
/ / \ \
+---+---------------+---+ A/D 32 bit bus
Example of an arbiter. Here, this is a very small IP core.
A copy of the PCI standard may contain a description of
the PCI bus arbitration operation and options. I believe
you can have peer level bus operation, as pictured above,
as long as the control signals on the bus, have the
appropriate pullup/pulldown resistors.
I don't see a reason for a PCI bridge chip, unless it is
the cheapest way to acquire the arbiter function.
I would say, you should purchase a copy of the PCI bus
spec. Or download one :-) For example, the second link
returned here, will give you a 322 page document. It is
a 3.8MB download.
This motherboard reference schematic, may help answer
some of your questions about the PCI bus. PDF page 49
shows some PCI bus termination resistors, and when no
device is driving the bus, something must be present
to keep the control signals deasserted. (Maybe a device
"parking" on the bus will do that too. Dunno.)
+-----------------+ To be master, a device must
| | request the bus and be granted
| v control of the bus. The master
PCI_Dev1 PCI_Dev2 (bus master) can then do
(Master) (Target) transactions to the other card
as its target. Once a master
+-----------------+ nas completed a transaction, if
| | the other device wants to become
v | master, it can request the bus too.
PCI_Dev1 PCI_Dev2 This is a form of peer to peer
(Target) (Master) communication. Each target needs
a unique bus decode, done with a
resistor and IDSEL (PDF page 57
of the PCI bus standard).
Perhaps your TI FAE can help you with the details ?
This document has a little info about the PCI
interface on that processor family.
This is how some other people connected their processors...
Just a guess,