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RELEASED
DATA SHEET
PM7366 FREEDM-8
ISSUE 4
PMC-1970930
FRAME ENGINE AND DATA LINK MANAGER
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA,INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
21
Pin No.
Pin Name
Type
-PI
-BI
Function
DEVSELB
I/O
K20
K1
The active low device select signal (DEVSELB)
indicates that a target claims the current bus
transaction. During the address phase of a
transaction, all targets decode the address on the
AD[31:0] bus. When a target, recognizes the address
as its own, it sets DEVSELB low to indicate to the
initiator that the address is valid. If no target claims
the address in six bus clock cycles, the initiator
assumes that the target does not exist or cannot
respond and aborts the transaction.
When the FREEDM-8 is the initiator, DEVSELB is an
input. If no target responds to an address in six
PCICLK cycles, the FREEDM-8 will abort the current
transaction and alerts the PCI Host via an interrupt.
When the FREEDM-8 is the target, DEVSELB is an
output. DELSELB is set low when the address on
AD[31:0] is recognised.
When the FREEDM-8 is not involved in the current
transaction, DEVSELB is tri-stated.
FREEDM-8 is updated on the rising edge of PCICLK
or sampled on the rising edge of PCICLK depending
on whether it is an output or an input.
LOCKB
Input
L18
L2
The active low bus lock signal (LOCKB) locks a target
device. When LOCKB and FRAME are set low, and
the FREEDM-8 is the target, an initiator is locking the
FREEDM-8 as an "owned" target. Under these
circumstances, the FREEDM-8 will reject all
transaction with other initiators. The FREEDM-8 will
continue to reject other initiators until its owner
releases the lock by forcing both FRAMEB and
LOCKB high. As a initiator, the FREEDM-8 will never
lock a target.
LOCKB is sampled using the rising edge of PCICLK.
REQB
Output
E17
E4
The active low PCI bus request signal (REQB)
requests an external arbiter for control of the PCI bus.
REQB is set low when the FREEDM-8 desires access
to the host memory. REQB is set high when access
is not desired.
REQB is updated on the rising edge of PCICLK.