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CHAPTER 3 INTERRUPTS
3.8 Operation Flow of and Procedure for Using the Extended
Intelligent I/O Service (EI2OS)
Figure 3.8-1 is a diagram of the EI2OS operation flow. Figure 3.8-2 is a diagram of the
EI2OS use procedure.
■EI2OS Operation Flow
Figure 3.8-1 EI2OS Operation Flow
ISE = 1
DIR = 1
BF = 0
SE = 1
DCT = 00
IF = 0
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
YES
NO
Interrupt request issued
from internal resource
Reading ISD/ISCS
Interrupt sequence
End request from resource
Data indicated by IOA
(Data transfer)
Memory indicated by BAP
Data indicated by BAP
(Data transfer)
Memory indicated by IOA
Update value
depends on BW.
Update value
depends on BW.
Updating IOA
Updating BAP
Decrementing DCT
Setting S1 and S0
to "00"
Clearing resource
interrupt request
CPU operation return
Setting S1 and S0
to "01"
Clearing ISE to "0"
Interrupt sequence
⇓⇓
BAP : Buffer address pointer
I/OA : I/O address pointer
ISD :EI
2OS descripter
ISCS :EI2OS status
DCT : Data counter
ISE : EI2OS enable bit
S1 and S0: EI2OS end status
Setting S1 and S0
to "11"