Operator
Familiarization—MicroLab
|
Instruction
Programming
the
MicroLab
|
Display
and
Keypad
Both
the
MicroLab! keypad
and the
display
can
be
accessed
by
your
program.
The
keypad
and
display
exist at
1/O
addresses. These addresses
are specific to
the
personality card
you're
using.
Reading
the
Keypad
The MicroLab! keypad
is
fully
hardware
decoded,
and
exists
as
a
single
byte
of
information
at!/O
location
XXX2.
(The
X’s
vary
with
the personality
card used.
See the
supplement
for
your personality card.)
The keypad
byte
is
organized
as
shown
in
Figure 2-5.
mney
Key
Pressed
Key
Code
Strobe
Fig.
2-5. The
MicroLab
|
Keypad Byte.
Bits
5
and
6
of
the
byte
are
not
used. Bits
O
through 4
equate
to
a
hexadecimal
code
for
each
key.
The
key
codes
are
listed
in
Table 2-3.
When
a
key
is
pressed, the
keypad
data
is
stored
in
a latch
at location
XXX2.
In
order
to
clear
that
latch
in
preparation
for anewkey
press,
you
must
write
to
XXX2.
For example,
if
you
wanted
to
read
in a
new
key
value,
you
would have to
do
the
following procedure:
1.
Write
to!/O
address
XXX2.
It
doesn’t
matter what
you
write. This action
clears the
key
latch.
2.
Wait
for
7 milliseconds.
It
takes this
long for
the
latch to
clear.
You
can
use
NOP
instructions
to delay 7
milliseconds
if
necessary.
3.
Read
I/O address
XXX2.
4.
Test
for
bit
7 high.
This
indicates
that
a
key
has been
pressed.
If
bit
7
is
low, loop
back
and read the address
again.
5.
Read
the
key
code
that
was
entered.
The
RESET
and
SPECIAL
keys
use dedicated
lines
in
hardware, and cannot
be
read
from
XXX2.
2-10
Table
2-3
MicroLab
|
Key
Codes
Key
Coding
80
81
82
83
84
85
86
87
88
89
8A
8B
8c
8D
8E
8F
90
INC
91
LOAD
ADDRESS
92
LOAD DATA
93
SHIFT
94
GO
95
AUTO
96
NO
KEY
00
T™MONOMFOHAYNFAHMBWN=0
o
m
°
Writing
To
The Display
The
MicroLab
|
readout
is
an 8-digit latched hexadecimal
display. The display
can
be
accessed
at
MicroLab
|
port
XX80.
The
address
of
the
port
is
dependent
on
the
personality
card. The display
is
organized
in
the
manner
shown
in
Fig.
2-6
Notice
that
each digit
has
a
hexadecimal
value
assigned
to
it.
You'll
also
see
in
Table
2-4 that
each displayable
character
has
a
value
assigned
to
it.
The
digit
value
is
used
in
combination with
the
value
of
the
character
you
want
to
display,
in
the
following
manner.
Using
the 8085 Personality
Card,
suppose
you
wanted
to
display an upper
case
H
on
digit number
5. In
Fig.
2-6
you
can
see
that
digit
5
has
a
value
of
AO.
Checking
in
Table 2-4,
you'll
find
that
an upper
case
H
is
represented
by
a
hexadecimal
11.
In
order
to
display
H
on
digit 5, you
must
ADD
thedigit's
address with the character
value.
Digit
Value
=
AO
Character
Value
=
+11
=B1
Summary of Contents for 067-0892-00
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