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Chapter 2 Programming Details
PCI Arbitration Assignments
The integrated PCI/X arbiters internal to the MPC8540 and the PCI6520 bridges provide PCI arbitration
for the MVME3100. The MPC8540 provides arbitration support for itself and the four PCI-X devices on
PCI bus A.
The PCI6520 secondary PCI/X interface arbiters support external bus masters in addition to the
PCI6520. One secondary arbiter provides arbitration for the PMC sites on PCI bus B, and the other
provides arbitration for the PMCspan and USB host controller on PCI bus C.
The arbitration assignments on the MVME3100 are shown in the follow table so that software may set
arbiter priority assignments if necessary.
Table 2-9. PCI Arbitration Assignments
PCI Bus
A
A
A
A
B
B
B
B
C
C
Clock Distribution
The clock function generates and distributes all of the clocks required for system operation. The clock
tree is designed in such a manner as to maintain the strict edge-to-edge jitter and low clock-to-clock
skew required by the devices. Additional clocks required by individual devices are generated near the
devices using individual oscillators.
along with their frequency and source. The clock tree A frequencies on bus A have a default
configuration of 66 MHz. The 33/66/100 MHz clocks are dynamically configured at reset depending on
the state of the PCIXCAP and M66EN pins on bus B.
Note
The PCI clock trees A, B, and C are not required to be synchronized with each other.
34
MVME3100 Programmer's Guide (V3100A/PG1)
Arbitration Assignment
MPC8540 PCI_REQ/GNT[0]
MPC8540 PCI_REQ/GNT[1]
MPC8540 PCI_REQ/GNT[2]
MPC8540 PCI_REQ/GNT[3]
PCI6520-1 S_REQ/GNT[0]
PCI6520-1 S_REQ/GNT[1]
PCI6520-1 S_REQ/GNT[2]
PCI6520-1 S_REQ/GNT[3]
PCI6520-2 S_REQ/GNT[0]
PCI6520-2 S_REQ/GNT[1]
PCI Master(s)
sATA Controller
TSI148 VME Controller
PCI6520 (Bus A to Bus B bridge)
PCI6520 (Bus A to Bus C bridge)
PMC site 1 primary master
PMC site 1 secondary master
PMC site 2 primary master
PMC site 2 secondary master
USB Controller
PMCspan
Table 2-10 on page 35
lists the clocks required on the MVME3100
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