Table of Contents
Advertisement
Section IV
c. In accordance with the name of a flip-flop which is
the source of the signal.
d. In accordance with the name of the bus which
carries the signal.
4-16.
Since most of the circuits on the two interface
cards employ positive logic, signal names are positive-true.
The following
paragraphs describe the expression
"positive-true name" as applied to each of the four types of
signal names.
4-17.
When a signal is named in accordance with a
condition, the signal level is +3.5 volts when the condition
exists, and +0.2 volts when the condition does not exist.
For instance, the TO (track origin) signal is +3.5 volts when
the disc track origin is passing the read/write heads, and
+0.2 volts when the track origin is not passing the read/
write heads. Similarly, the "not" RY signal is +3.5 volts
when the disc is not ready, and +0.2 volts when it is ready.
4-18.
In further accordance with the principle of
positive-true signal names, a signal which is named in the
imperative mode becomes +3.5 volts to bring about the
action commanded. For instance, the Flag FF is cleared
when the CLF (clear flag) signal changes from +0.2 volts to
+3.5 volts.
4-19.
When a signal is named in accordance with the
flip-flop which is its source, the signal taken from the set
side of the flip-flop is +3.5 volts when the flip-flop is in the
set condition, and +0.2 volts when the flip-flop is in the
reset condition. For instance, when the Control Bit FF is
set, the CB signal is +3.5 volts.
4-20.
When a signal is named in accordance with the bus
which carries it, the signal is +3.5 volts when the bus carries
a logic 1, and +0.2 volts when it carries a logic O.
12606B
4-21.
DISC SIGNALS. All control signals and data
signals that enter or leave the disc pass through the two
interface cards. The control signals are illustrated in
figure 4-1. The operating and service manual for the disc
memory provides information on the timing of signals
originating in the disc.
4-22.
MULTIPLE DISCS. If more than one disc is
connected to the computer, each disc has its own interface
kit.
4-23.
LOCATION OF CONTROLS. Table 4-1 gives the
location of controls mentioned in the detailed theory
discussion in this section.
Table 4-1. Location of Controls
CONTROL
LOCATION
PRESET switch
Computer
POWER switch
Computer
Power ON switch
Disc power supply
4-24.
ADDITIONAL INFORMATION. Logic diagrams
for the two interface cards are furnished in figures 5-3 and
5-5, in section V of this manual. Interconnections between
the two cards, and between each card and the disc memory,
are listed in tables 5-3 and 5-5. In the logic diagrams and
tables, pins marked with an asterisk plug into the
48-contact interface connector. Pins without an asterisk
plug into the 86-contact backplane connector.
4-25.
Connections from the cards to the computer are
listed in the backplane wiring list for the computer.
4-26.
Tables 4-2 and 4-3 list the flip-flops and registers
on the two interface cards, and briefly describe the
functions they perform.
I
I
I
I
fool ~ __ - -
SECTOR
000 ------"~o-ll
""'I ~""--SECTOR OOl---~~1
--
1
1
I
1
TOI'~--~------------~--~------------~--_~i
LJ
I
I
I
I
U
I
1
1
1
SC
I
1
1 - - - - - - , r+--,I "
~
.----,
r - -
----~~-------------~-
UI
U-
U
U
I
I
I
I
Vii
OR
R
I
1
I
;..1--oNN'------_ _
--------~I
__________________
~r__l
I
2032-2
4-2
I
I
BC-----------~
I
1.nJ
N
NOTES:
1.
NOT TO SCALE HORIZONTALLY
2.
THE
iN
OR
R
SIGNAL SHOWS WRITING OR READING
IN THE FIRST TWO SECTORS
Figure 4-1. Control Signals Transferred to and from Disc Memory, Timing Chart
Advertisement
Table of Contents
