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Stcrage
Location
80
Contents
Trap priority register CMMSK)
Branch condition register CEA)
81
82
83
84
85
86-87
GS channEl External conditions
Error count (6 Eits
1
2-7; Bits O,
1=11)
GT channel external ccnditicns
GD channel External conditions
Unit identificaticn halfwcrd.
~rap
Priority
(~~SK)
Register
Bit 0
1
2
4
5
6
7
Channel high priority trap
2311 Disk Control traf
Channel low priority trap
2540 Punch trap
Communication Bit service trap
Ccrrmunications character service
trap
I.evel-1 priority hold.
Branch Condition (BA) Register
Bit 0
Channel-0 Interrupt I.at ch
1
Mode Bit 0
2
Mode Bit 1
3
Mode Bit
2
4
IPI I.a tch
5
LS zone Bit 0
6
LS Zone Bit 1
7
IS Bit 2.
GS Channel External Conditions
Bit 0
1
2
3
4
5
6
7
Data chain request
Bufferea device latch
Channel-1 burst latch
channel parity-error latch
Initial selection latch
Channel-1 interruption latch
Spare
Suppress control latch
GT Channel External Conditions
Bit 0
1
2*
3*
4
5
6
7
Address in
Not select-in
Service-in
Status-in
Operational-in
Not request-in
Channel identification latch
channel diagnostic latch
*
Service-In and Status-In conditions from
the interface are detectable in GT only
if neither Command-Cut nor Service-Out
have yet teen trought up in response to
service-In or Status-In.
GD Channel External Conditions
Bit 0
1
2
3
4
5
6
7
Opera tiona 1-cut
service-out
Address-cut
command-out
Spare
Select-out
Spare
suppress-out
Unit Identification Halfword
Byte 0
Bits
0 1 2
000
0 0 1
0 1
x
1 0 0
Meaning
Integrated 1052, 1403, or 2540
Multiplexer channel
Selector channel
Integrated communications attachment
If bits 0-2 indicate the MPX channel
feature, bits 3-6 are used for various
functions under microprogram control.
If bits 0-1 indicate the selector
channel feature, bits 2-6 are used as a
timeout counter for interface sequences.
Bit 7 is used to indicate whether any
unit or channel status rray be stored
directly in a CSW, or whether the
interruption rr:ust be put in the interrupt
tuf fer and subsequently cleared by an I/O
instruction or an I/O interrupt.
Byte 1, for the selector channel or
multiplexer feature, contains the current
device address.
GA (Channel Conditions)
A set/reset word with CS-field=B is used to
set or reset bits in GA.
The set/reset bit
in the set/reset word is ignored whether
the bits are to be set or reset.
The K-bit
values determine which tits are set or
reset.
If a K bit=l, the corresponding bit
in GA is set; if a K bit=O, the
corresponding bit in GA is reset.
Eit
Meaning
-0-
Selective reset.
Drops
operational-out for 6 microseconds.
1
Service-out
2
Address-out
3
Command-out
4
Initial selection (Inhibits
low-priority traps during an initial
selection sequence.
That is, data
or chaining traps for channel O,
chaining or status traps for channel
1.)
5
Select-out
6
Channel reset (diagnostic).
Resets
channel latches.
7
Spare
2025 FEMM (7/69)
2-45
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