LSI LSI53C1000, Technical Manual

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PCI Bus Interface Signals 3-7
3.3.3 Interface Control Signals
Table 3.4 describes the Interface Control Signals group.
Table 3.4 Interface Control Signals
Name Bump Type Strength Description
ACK64/ AB1 S/T/S 8 mA PCI Acknowledge 64-bit transfer is driven by the current bus
target to indicate its ability to transfer 64-bit data.
REQ64/ AA2 S/T/S 8 mA PCI Request 64-bit transfer is driven by the current bus master
to indicate a request to transfer 64-bit data.
FRAME/ P2 S/T/S 8 mA PCI Cycle Frame is driven by the current master to indicate the
beginning and duration of an access. FRAME/ is asserted
to indicate that a bus transaction is beginning. While
FRAME/ is deasserted, either the transaction is in the final
data phase or the bus is idle.
TRDY/ P3 S/T/S 8 mA PCI Target Ready indicates the target’s ability to complete the
current data phase of the transaction. TRDY/ is used with
IRDY/. A data phase is completed on any clock when both
TRDY/ and IRDY/ are sampled asserted. During a read,
TRDY/ indicates that valid data is present on the AD bus.
During a write, it indicates that the target is prepared to
accept data.
IRDY/ N4 S/T/S 8 mA PCI Initiator Ready indicates the initiator’s ability to complete
the current data phase of the transaction. IRDY/ is used with
TRDY/. A data phase is completed on any clock when both
IRDY/ and TRDY/ are sampled asserted. During a write,
IRDY/ indicates that valid data is present on the AD bus.
During a read, it indicates that the master is prepared to
accept data.
STOP/ R2 S/T/S 8 mA PCI Stop indicates that the selected target is requesting the
master to stop the current transaction.
DEVSEL/ R1 S/T/S 8 mA PCI Device Select indicates that the driving device has
decoded its address as the target of the current access. As
an input, it indicates to a master whether any device on the
bus has been selected.
IDSEL L3 I N/A Initialization Device Select is used as a chip select, in
place of the upper 24 address lines, during configuration
read and write transactions.