Functional Description
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
15-9
Figure 15-5. Target-Initiated Terminations
Note that when an initiator is terminated by
PCI_STOP
, it must deassert its
REQ
signal for a
minimum of two PCI clocks (of which one clock is needed for the bus to return to the idle state).
If the initiator intends to complete the transaction, it should reassert its
REQ
immediately
following the two clocks or potential starvation may occur. If the initiator does not intend to
complete the transaction, it can assert
REQ
whenever it needs to use the PCI bus again.
The VCOP terminates a transaction in the following cases:
Eight PCI clock cycles have elapsed between data phases. This is a latency disconnect (see
Figure 15-5).
AD[1–0] is 0bx1 (a reserved burst ordering encoding) during the address phase and one
data phase has completed.
The PCI command is a configuration command and one data phase has completed.
A streaming transaction crosses a 4K page boundary.
A streaming transaction runs out of I/O sequencer buffer entries.
A cache line wrap transaction has completed a cache line transfer.
Another target-initiated termination is the retry termination. Retry refers to termination requested
because the target is currently in a state where it is unable to process the transaction. This can
PCI_CLK
PCI_FRAME
PCI_IRDY
PCI_DEVSEL
PCI_TRDY
PCI_STOP
Disconnect A
Disconnect B
Retry
PCI_CLK
PCI_FRAME
PCI_IRDY
PCI_DEVSEL
PCI_TRDY
PCI_STOP
Latency disconnect
PCI_CLK
PCI_FRAME
PCI_IRDY
PCI_DEVSEL
PCI_TRDY
PCI_STOP
Target abort
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...