Intel 1.00 GHz YK80542KC0013M User Manual

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DBSY# is a copy of the Data Bus Busy signal. This copy of the Data Bus Busy signal 
(DBSY_C2#) is an output only.

The DEFER# signal is asserted by an agent to indicate that the transaction cannot be guaranteed in-
order completion. Assertion of DEFER# is normally the responsibility of the priority agent.

The Defer Enable (DEN#) signal is driven on the bus on the second clock of the Request Phase on 
the Ab[4]# pin. DEN# is asserted to indicate that the transaction can be deferred by the responding 
agent.

The Data Bus ECC Protection (DEP[15:0]#) signals provide optional ECC protection for Data Bus 
(D[127:0]#). They are driven by the agent responsible for driving D[127:0]#. During power-on 
configuration, bus agents can be enabled for either ECC checking or no checking.

The ECC error correcting code can detect and correct single-bit errors and detect double-bit or 
nibble errors. 

The Deferred Hit (DHIT#) signal is driven during the Deferred Phase by the deferring agent. For 
read transactions on the bus DHIT# returns the final cache status that would have been indicated on 
HIT# for a transaction which was not deferred. DID[9:0]# (I/O)

DID[9:0]# are Deferred Identifier signals. The requesting agent transfers these signals by using 
A[25:16]#. They are transferred on Ab[25:16]# during the second clock of the Request Phase on all 
transactions, but Ab[20:16]# is only defined for deferrable transactions (DEN# asserted). 
DID[9:0]# is also transferred on Aa[25:16]# during the first clock of the Request Phase for 
Deferred Reply transactions.

The Deferred Identifier defines the token supplied by the requesting agent. DID[9]# and DID[8:5]# 
carry the agent identifiers of the requesting agents (always valid) and DID[4:0]# carry a transaction 
identifier associated with the request (valid only with DEN# asserted). This configuration limits the 
bus specification to 32 logical bus agents with each one of the bus agents capable of making up to 
32 requests. 

 shows the DID encodings.

DID[9]# indicates the agent type. Symmetric agents use 0. Priority agents use 1. DID[8:5]# 
indicates the agent ID. Symmetric agents use their arbitration ID. DID[4:0]# indicates the 
transaction ID for an agent. The transaction ID must be unique for all deferrable transactions issued 
by an agent which have not reported their snoop results.

Agent Type

Agent ID[3:0]

Transaction ID[4:0]