RCA Spectra 70 - Page 87

4
2
3
4
Device Control Electronics is
Asked for the
Device Address
Is Device Control
Electronics Operable?
Yes
Receive Standard Device
Byte from Device
Control Electronics
Yes Is This a Multiplexor
.-------------/ Channel Interrupt?
Fetch Appropr i ate
Subchannel Regi sters
and Transfer Them to
Scratch Pad Memory
~. _______________ .J
(See Note 2)
5
No
6
7
8
No
Is This a
Termination Interrupt?
Yes
Set Termination
Interrupt Bit in
Channel Status
Byte
Test for
Incorrect Length
No
Store Standard Device
Byte in Appropriate
Registers in Scratch Pad
Memory (If
Required)
t
Next Instruction
No
2
Yes
8
Input/Output Operation
Generate an All Z",ro
Standard Devi ce Byte
and Store it into 1/0
Channel Registers in
Scratch Pad Memory
~-----~-------~
Set Incorrect Length
Bit in Channel
Status Byte
Figure 11. Functional Logic of Interrupt Servicing
78