SPECIAL
Key
Debounce
>
AA
In
the
lower right
corner
of
schematic
4,
you'll
find
the
SPECIAL
Key Debounce
circuitry.
On
schematic
5,
you
can
see that
the
SPECIAL
key
is
connected
with
its
own
line
to
the
Main
Interconnect
board.
When the
SPECIAL
key
is
pressed, the
SPECIAL
line
goes
low,
and the
J-K
inputs
to
U1060A
are
forced
low.
The
KCLK
clock
input
to
U1060A
originates
from
the
Baud
and
Clock
Generator
circuitry.
As
soon
as
KCLK
goes
high,
pin
7
of
U1060A
goes
high,
forcing
the
SPECIAL
line
to
the
personality
card
low.
What
the personality
card does with the
SPECIAL
line
is
entirely
dependent
on
the
personality card.
U1060A
is
reset
by
the
BSP
line from the Breakpoint
Enable
logic
on
schematic
5.
Interrupt Gating
»
HAJ
All
the interrupts that
can be
generated
on
the
Main
Interconnect
board (keypad interrupt, serial
1/O
port
interrupt,
etc.)
all
come
together at the Interrupt
Gating
Theory
of
Operation—MicroLab
|
Instruction
logic.
All
the
interrupt
lines
are
ORed
together
by
U3030A
and
U2030B
to
generate
an
IREQ
pulse
that
is
sent
to
the
personality
card.
When
the
personality card
receives the
interrupt,
it
begins
polling
all
the
device
status registers
on
the
Main
Interconnect
board
to
find
the
interrupting
device.
-5
Volt
Regulator
And
+5
Volt
Crowbar
>
FAB}
In
the
upper right
corner
of
schematic
5 is
the -5
volt
regulator.
U8084
is
the
regulating
device.
Some
personality cards require
—5
volts
for
proper
operation.
Above the
regulator
is
the
+5 volt
overvoltage crowbar
circuit.
If
the
+5 volt
line
approaches
+6
volts,
zener diode
VR8096
pulls
the gate
input
of
Q9096
high
enough
to
turn
the
SCR
on.
When
the
SCR comes
on,
it
shorts
the
+5 volt
power supply
and
blows
the
+5 volt
supply
fuse.
Содержание 067-0892-00
Страница 9: ...MicroLab Instruction 2827 1 The TEKTRONIX MicroLab I vi REV A JUN 1980...
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Страница 102: ...MICROLAB AlddNS Y3MOd 3YHNDIS...
Страница 103: ...JANVd LNOYS Z AHNDIS MICROLAB...
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Страница 110: ......