IBM 1710 Manual page 46

Core Storage
Figure 29. Select
ADC
Register Instruction Data Flow
a group of 20 terminal points. A total of 20 terminal
addresses is available if all 400 contact sense points are
installed. For the purposes of programming, the term-
inal block can be thought of as consisting of two parts
or halves with 200 terminal points (10 terminal ad-
dresses) on each half. Positions
QI0
and
Qll
of the in-
struction must specify one of the 20 terminal addresses.
When the instruction is executed, the 20 terminal
points at the terminal address specified in
QI0
and
Qw
and all of the terminal points for the remaining
higher-numbered terminal addresses (in that "half"
of the terminal block) are scanned and read into core
storage. The following chart lists the twenty terminal
addresses and the corresponding points that are scan-
ned. Note, for example, that a terminal address of 03
in
QI0
and
Qll
causes the program to scan and read into
core storage terminal points 60 through 199.
Terminal Points Terminal Points
Address Scanned Address Scanned
00 000-199 10 200-399
01 020-199
11 220-399
02 040-199 12 240-399
03 060-199 13 260-399
04 080-199 14 280-399
05 100-199 15 300-399
06 120-199 16 320-399
07 140-199 17 340-399
08 160-199 18 360-399
09 180-199 19 380-399
For another example, the terminal address 10 causes
200 terminal points to be scanned and read into core
storage. The contact points that must be scanned most
frequently should be installed so that they are assigned
46
to the highest-numbered terminal addresses on either
"half" of the contact sense terminal block.
As the contacts are scanned, the status of each one
is entered in core storage beginning at the location
specified by the P address of the instruction. The status
of the 20 contacts of each terminal address group is
stored in seven positions of core storage. (Flags bits
already existing in the seven core storage positions are
removed.) The status of the first two points is recorded
in the first of the seven position; the status of the re-
maining 18 points is stored in the second through
seventh positions as shown in the following diagram.
III
Seven Positions of
I I I
Core Storage -----
Terminal
Points
20-39
r---1
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
1
J
1
J
1
j
1
1
1
J
38~------------------------~
39