IBM 1710 Manual page 37

number of addresses cannot exceed 100. The addresses
(00-99) are assigned by the user.
Process Operator
Units
1713 Manual Entry Unit
(7 maximum)
1714 Sense Switch Unit
(20 maximum)
1715 Digital Display Unit
(20 maximum)
1717 Output Printer
(20 maximum)
Number of Addresses
Required
13
4
4
The following rules should be observed when making
the address assignments:
1. Unit response codes for all units must be consecu-
tive, beginning with 00 and ending with 19, if all
twenty units are involved.
2. All addresses assigned to all units must be con-
secutive, subject only to the provision of the next
rule.
3. The addresses assigned to anyone unit must be
consecutive and must not go beyond the numbers
possible with one tens digit (e.g., 10-19, 20-29,
etc.) , except for the 1713 where addresses assigned
must not exceed two tens digits.
This rule applies if there is a conflict with in-
structions in rule 2. For example, if the last ad-
dress used for any unit was 48 and the next ad-
dresses to be assigned were the 13 necessary for a
Manual Entry Unit, 49 through 61 could not be
assigned to the Manual Entry Unit because three
tens digits are involved. Instead, 49 would not be
used, and addresses 50 through 62 would be as-
signed. If enough devices are connected so that
all of the 100 available addresses are used, the
sequence of units in the addressing scheme may
have
to
be carefully arranged to prevent the
group of addresses for a Manual Entry Unit from
beginning with an address containing an 8 or 9
units digit.
SIOC Characteristics
Transmission to and from the control system is serial
by character. Operational speed of the attached units
depends on the capability of each unit and upon the
arrangement of the 1620 Data Processing Unit pro-
gram. The maximum transmission rate is 80 characters
per second, 12.5 milliseconds (ms) per character.
Although characters are transferred serially to and
from each unit, the relatively fast internal speed of
the computer as compared to the speeds of the individu-
al input/output units, and the design of the Serial In-
put/Output Channel permits the operation of the units
to be over lapped. From the standpoint of the pro-
grammer, the program is "looping" through a series
of input and output operations, but from the stand-
point of the process operator, data can be displayed,
read, and printed almost simultaneously.
The sloe cable is a single, multi-wire cable with a
connection for each input or output unit, as required.
Cable design permits an individual unit to be con-
nected or disconnected without disturbing the oper-
ation of remaining units on the cable. The cable can
be continuous with junctions for attached units or
branching cables for units in remote locations. The
maximum accumulated length of cable is 2,500 feet.
The Basic Interrupt, Input/Output Interrupts, and
Random Addressing special features are prerequisites
for the installation of the Serial Input/Output Chan-
nel.
Input/Output Data Register
The Input/Output Data Register
(IODR) ,
a part of
the slOe feature, is a single-character register that acts
as buffer storage for input data from an attached unit
and for output data from 1620 core storage.
IODR
is a
7-bit register with the following bit configuration:
XOC8421
The proper encoding and decoding of input/output
data is accomplished by the 1620 as each character is
transmitted between core storage and
IODR.
The bits for
each character are transmitted in parallel between
IODR
and the slOe unit and between
IODR
and core storage.
Appendix D is a chart of
IODR
character codes.
Output Operations
The selection of the output unit (1715 Digital Display
Units or 1717 Output Printer) and the transmittal of
data are accomplished by the Write Numerical Output
Channel (WNOC-88) or Write Alphameric Output
Channel (WAOC-89) instruction with a
Q7
digit of 5,
which identifies it as an slOe operation. Only one in-
struction is needed to completely transfer one character
from core storage to an output unit. The address of the
output unit is contained in QI0 and Qll. The P part of
the instruction is the core storage address of the char-
acter transmitted. If alphameric data is being trans-
ferred, the P address must be an odd number, as in
normal output operation.
Upon execution of the output instruction, the 2-digit
code in QI0 - Qll is sent to the Terminal Address Se-
lector
(TAS)
which selects the proper unit. The char-
acter at the P address in core storage is encoded and
stored in
IODR.
At this point, the 1620 and
TAS
are re-
leased for other programmed operations; slOe remains
37