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PCI Bus Controller
Freescale Semiconductor
22-27
22.3.3.2
PCI Arbiter Status Register (PASR)
22.4
Functional Description
shows the PCI controller provides master and target PCI bus interfaces. The internal master,
or initiator, interface is accessible by any crossbar switch bus master, such as the processor core. The target
interface provides external PCI masters access into as many as six memory windows of address space. PCI
arbitration manages by the internal PCI arbiter or off-chip. (See
).
Section 22.3, “Memory Map/Register Definition,”
control and provide
information about multiple interfaces. An additional configuration interface allows internal access through
4–1
EXTMPRI
External master priority levels. Bit 1 controls the priority for the device using PCI_REQ[0] and PCI_GNT[0] pins,
bit 2 for PCI_REQ[1] and PCI_GNT[1], etc.
0 Low
1 High
0
INTMPRI
Internal master priority level
0 Low
1 High
Address: 0xFC0A_C004 (PASR)
Access: User read/write
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17
16
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
R 0
0
0
0
0
0
0
0
0
0
0
EXTMBK
ITLMBK 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
w1c
1
w1c
1
Reset 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
Bits 20-16 are write-one-clear (w1c).
Hardware can set w1c bits, but cannot clear them.
Software can clear w1c bits that are currently set by writing a 1 to the bit location. Writing a 1 to a w1c bit that is
currently a 0 or writing a 0 to any w1c bit has no effect.
Figure 22-34. PASR Register
Table 22-24. PASR Field Descriptions
Field
Description
31–21
Reserved, must be cleared.
20–17
EXTMBK
External master broken. Indicates an external master time-out has occurred. Bit 17 reports the time-out status for
the device using PCI_REQ[0] and PCI_GNT[0] pins, bit 18 for PCI_REQ[1] and PCI_GNT[1], etc. A CPU interrupt
generates if corresponding PACR[EXTMINTEN] bit is set. Software must write a 1 to each bit location or write a 1
to the software reset bit, PACR[RA], to clear.
16
ITLMBK
Internal master broken. Indicates a PCI controller master time-out has occurred. A CPU interrupt generates if
PACR[INTMINTEN] bit is set. Software must write a 1 to this bit location or write a 1 to the software reset bit,
PACR[RA], to clear.
15–0
Reserved, must be cleared.
Table 22-23. PACR Field Descriptions (continued)
Field
Description
Содержание MCF54455
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