MB86613S Datasheet, PDF (52/134 Pages) Fujitsu Component Limited. – IEEE1394 Open HCI Controller

Preliminary
4. Context Program Controller (CPC)
Basically Context Program Controller’s (CPC) state machine consists of Program Load, Program Analysis,
and Interrupt Handle.
CPC starts the operation after the ContextControl.run bit is set by the software. CPC, however, stops the
operation when ContextControl.active and .dead bits are cleared as a result of ContextControl.run bit cleared
by the software.
In Program Loading Unit (PLU), MB86613S loads the context program from the host memory in which the
CommandPtr.descriptorAddress indicates and stores the program into the on- chip work RAM.
In Program Analysis Unit (PAU), MB86613S analyzes the loaded context program and moves the required
transmit- packet from/to the work RAM/Host memory to/from FIFO.
In Interrupt Handling Unit (IHU), MB86613S handles/controls the event- code and interrupt as a result from
the program analysis. In this case, if Z field in the last descriptor contains ”1” or more, the device stores the
address set in the branchAddress field of the last descriptor in the CommandPtr.descriptorAddress field in
order to store the next context program and returns to the program loading unit.
Figure 4.1 shows the state machine diagram, and Figure 4.2 shows the flag transition of ContextControl Reg-
ister with the explanation as follows:
1) If the wake bit is set by software, clear the wake bit and set the active bit, then go to the program loading unit.
When starting the CPC with the run bit, set the active bit and go to the program loading unit.
2) When the program analysis is completed, go to the interrupt handling unit. If an error occurred in the IHU,
set the dead flag and clear the active bit, then wait until the dead flag is cleared by software.
3) If the next context program to be processed is not prepared yet, clear the active bit and wait until the wake bit
is set by software; i.e. until the next context program to be processed is prepared.
”run” : ’0’
run=0
Start
error _INT
error
INT
run=1
Load
Analyze
end
z>0
z=0
INT
Fig. 4.1 Block Diagram of CPC State Machine
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