Table of Contents
Advertisement
The signal which leaves l3-C16-S provides an enable for keyboard entry.
When
a key on the keyboard is depressed, code bars within the TTY engages and rotates
a cam containing ten lobes.
As the cam rotates, each lobe is positioned with
its respective code bar in such a manner that only one code bar can be monitored
at a time.
If a lobe makes contact with a code bar, indicating a mark condition,a logical
11111 is sent to the controller via the keyboard line (23-Cll-4).
If the lobe
fails to make contact with a code bar (indicating a space condition), a logical
110 11 is sent to the controller.
Circuits in the controller convert the non-logic
level signals to logic l-evel.
The first code bar monitored during cam rotation represents a Start signal to
synchronize the controller logic with cam rotation speed.
The code bar for the
Start signal will always cause a logical 1I011 to appear at TP ~ of the Z19
module (page 23).
This
signal is shaped into a 100 nsec pulse by the Start
Detector (Page 23) which is used to:
(1)
Set the Mechanical Busy FF (23-C06-2).
(2)
Set the Clock Control FF (19-C04-l9).
(3)
Enable setting the Lost Data FF (17-C14-2S).
If the Data Read FF is
set, the Lost Data FF will set at this time.
(4)
Clear Tape Motion FF (25.l-C17-20).
Setting of the Clock Control FF causes the Clock FF (Z18, page 19) to set.
Setting of the Clock FF causes a 100 nsec Clock 1 pulse to be generated at 19-
C05-9.
The Clock 1 pulse is applied to the Timing Chain (page 21), causing the
first FF (TP
~
) to set.
(All Timing Chain FFs had been previously cleared.)
This produces a logical 110 11 from 2l-C08-7 which prevents the contents of the
Data Holding register from being printed prematurely.
2-17
Rev. A
Advertisement
Table of Contents
Need help?
Do you have a question about the 1700 and is the answer not in the manual?
Questions and answers