IBM Series 1 User Manual page 30

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(~
o
Pol,! Identifier. This is a 5-bit outbound bus used
by the
channel to indicate the nature of the poll presently being
propagated to the I/O devices. The poll identifier is
always recognizable by I/O devices that are capable of cycle
stealing and/or presenting interrupts to the processor. The
channel places a value on the poll identifier bas prior to
raising the poll tag and holds it valid until a poll return
or burst return is received.
The significance of the poll identifiers is as follows:
(Poll ID bits are shown using logical representation for
active/inactive.)
Poll
identifier bit§. ~!~g
Q.1ll!!
00000 Poll for interrupt level
a
00001
Poll for interrupt level
1
00010
Poll for interrupt level
2
00011
Poll for interrupt level
3
00100
Poll for interrupt level
4
00101
Poll for interrupt level
5
00110
Poll for interrupt level
6
00111
Poll for interrupt level
7
01000
Poll for interrupt level
8
01001
Poll for interrupt level
9
01010
Poll for interrupt level 10
01011
Poll for interrupt level 1 1
01100
Poll for interrupt level 12
01101
Poll .for interrupt level
13
01110
Poll for interrupt level
14
01111
Poll for interrupt level 15
10000
Quiescent value
10100
Reserved
11000
Reserved
11100
Reserved
lXXOl Reserved
11X10 Reserved
11111
Poll for cycle steal
The Poll identifiers for interrupt levels 4--15 are not
used on current processors.
Processor I/O Channel 2-15