Operation Of Ei 2 Os - Fujitsu MB90895 Series Hardware Manual

3.5.13 Operation of EI
The flowchart of operation of the EI
below:
2
I Operation of EI
Interrupt request generate
from peripheral resource
ISE=1
YES
ISD/ISCS rread
Termination by the
termination request from
a peripheral resource ?
NO
DIR=1?
NO
Address setting for IOA
(Data transfer)
Address setting for BAP
IF=0?
NO
BF=0?
NO
DCT decrement
DCT="00 "?
H
NO
Set "00 " to S1, S0
B
Clear of peripheral
resourceinterruptewquest
CPU operation return
2
OS
2
OS using the microcode in the CPU is shown
OS
Figure 3.5-15 Flowchart of Operation of EI
NO
Interrupt processing
YES
YES
Address setting for BAP
Address setting for IOA
YES
Updating value
IOA updating
is by BW
YES
Updating value
BAP updating
is by BW
(-1)
2
YES EI OS terminate processing
Set "01 " to S1, S0
B
ISD
ISCS
IF
BW
BF
DIR
SE
DCT
IOA
BAP
ISE
S1,S0
YES
SE=1?
NO
(Data transfer)
Set "11 " to S1, S0
B
Clear ISE to "0"
Interrupt processing
CHAPTER 3 CPU
2
OS
2
: EI OS descriptor
2
: EI OS status register
: IOA update/fixed select bit
: Transfer data length specification bit
: BAP update/fixed select bit
: Data transfer direction specification bit
2
: EI OS terminate control bit
: Data counter
: I/O address pointer
: Buffer address pointer
2
: EI OS enable bit (ICR)
2
: EI OS status (ICR)
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