B-12 AlphaServer GS80/160/320 Service Manual
B.7.2 I/O Space Reads
Figure B– 3 I/O Space Read Transaction Flow Diagram
Source Processor
Issues a reference
to IO address X
IO Processor
IO Device
Source of PIORd Data
or
Destination of PIOWr Data
Arb
QIO PIORd
Q0 PIORd RespQ1 RdIO Comsig
Q2 IO Fill
QIO PIORd
