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PCI Bus Controller
22-18
Freescale Semiconductor
22.3.2.4
Target Control 1 Register (PCITCR1)
22.3.2.5
Initiator Window
n
Base/Translation Address Register (PCIIW
n
BTAR)
The following register figure describes the three initiator window base/translation address registers.
Address: 0xFC0A_806C (PCITCR1)
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
LD
0
0
0
0
0
0
PID P
0
0
0
0
0
0
0
WCD
WCT
W
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
1
0
0
0
Figure 22-18. PCITCR1 Register
Table 22-14. PCITCR1 Field Descriptions
Field
Description
31–25
Reserved, must be cleared.
24
LD
Latency rule disable. Applies only when ColdFire processor is target. When set, it prevents the PCI controller
from automatically issuing a retry disconnect due to the PCI 16/8 clock rule.Normal operation relies on the LD
bit being cleared.
If used, the bit must be set before the 15th PCI clock for first transfer and before the 7th clock for other transfers.
23–18
Reserved, must be cleared.
17
PID
Prefetch invalidate and disable. User sets this bit to invalidate all target prefetched data in the PCI controller.
Software can use this bit to invalidate any stale prefetched data when internal memory has been modified by an
internal resource. If prefetched data is currently transferring as read data to the PCI bus when this bit is set, data
transfers stop and the target interface disconnects the current PCI transaction. If set when prefetch data is
currently transferring from the internal bus, data for the current internal bus is marked invalid.
This bit is sticky and completely disables prefetching from the internal bus for PCI when set. This applies to
MEMORY
READ
MULTIPLE
, as well as
MEMORY
READ
and
MEMORY
READ
LINE
commands. This bit must be cleared
for the prefetch buffers to work.
16
P
Prefetch reads. Controls fetching a line from memory in anticipation of request from the external master. The
target interface continues to prefetch lines from memory as long as PCI_FRAME asserts and there is space to
store the data in the target read buffer.
Note:
This bit only applies to PCI reads in the address range for BAR1–5 (prefetchable memory).
Note:
Prefetching performs in response to a PCI memory-read-multiple command even if this bit is cleared.
15–9
Reserved, must be cleared.
8
WCD
Write combine disable. Applies only when device is target. When set, it prevents PCI controller from
automatically combining write data to be sent out on the internal bus as a burst. Instead, data transfers as soon
as possible on the internal bus as single-beat transactions.
Note:
Better target write performance is achieved when this bit cleared.
7–0
WCT
Write combine timer. Contains the timer value, in PCI clocks, used when a partial burst is buffered in the target
write data path and write data stops transfer to local memory from the external PCI device. Every time a
sequential beat of write data stores in the buffer, the counter resets with this value.
If partial burst data is buffered (activating the countdown counter) and this field is reprogrammed to a value less
than the current counter value, the counter jumps down to the new WCT value. This way, software can force the
write buffer to flush data to the internal bus more quickly than when the counter was initialized.
The reset value of the write combine timer is 0x08. All 8 bits are programmable.
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...