
DATA SHEET
PM7367 FREEDM-32P32
ISSUE 2
PMC-1991499
FRAME ENGINE AND DATA LINK MANAGER
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMER’S INTERNAL USE
290
Figure 29 – PCI Write Cycle
PCICLK
FRAMEB
AD[31:0]
C/BEB[3:0]
1
2
3
4
5
6
7
8
9
IRDYB
TRDYB
DEVSELB
T
Address Data 1
Data 2
Data 3
Byte En Byte En
Byte Enable
Bus Cmd
T
T
T
T
T
The PCI Target Disconnect (Figure 30) illustrates the case when the target wants
to prematurely terminate the current cycle. Note, when the FREEDM-32P32 is
the target, it never prematurely terminates the current cycle.
A target can terminate the current cycle by asserting the STOPB signal to the
initiator. Whether data is transferred or not depends on the state of the ready
signals at the time that the target disconnects. If the FREEDM-32P32 is the
initiator and the target terminates the current access, the FREEDM-32P32 will
retry the access after two PCI bus cycles.
During clock 1, an access is in progress.
During clock 2, the target indicates that it wishes to disconnect by asserting
STOPB. Data may be transferred depending on the state of the ready lines.
During clock 3, the initiator negates FRAMEB to signal the end of the cycle.
During clock 4, the target negates STOPB and DEVSELB in response to the
FRAMEB signal being negated.