Keyboard Led Data Decode - Datron 1061 Calibration And Servicing Handbook

43
cD4
0
1
0
I
0
1
0
1
0
1
1
0
1
17
16
5
c
0
0
1
1
0
0
1
1
0
0
0
1
15
c
0
0
0
0
1
1
I
1
0
0
t
1
M7
14
cD7
0
0
0
0
0
0
0
0
1
1
1
1
1
KEY
100
10
1
000
lOMQ
1
.1
10Q
AUTO
DC
KQ
KEYBOARD
I
INPUT
ZERO
M10
17
cD0
0
1
0
1
0
1
0
1
0
1
0
16
CDl
0
0
1
1
0
0
1
1
0
0
1
0
1
15
CD2
0
0
0
0
1
1
1
1
0
0
0
14
cD3
0
0
0
0
0
0
0
0
1
1
1
1
1
KEY
HOLD
RATIO
TEST
SPEC
(A_B)
dB
MAX
MIN
RESET
MAN
INPUÏ
FILTER
AC
FIG.3.45
CMOS
DATA
BUS
:
KEY SELECT CODING
ç
3.9.4
Keyboard L.E.D. Data Decode
@30294 sheet
1)
The
XKY
BRD
signal
is
inverted
by
01,
R7,
C1,
R6
partially
enabling
the
L.E.D. data latches
M4, M5,
M6,
M8, M9,
M'l
1 and M12 while information is
not
being
extracted
from the
keyboard encoders.
The
data
latches
are
divided into four
sets,
M6'and M4, M8 and M5,
M12
and
Ml1, M9
being
fully
enabled
from the XKD
SPø
-
XKD
SP3
lines resPectivelY'
On initialisation or after
a
change
of the instrument's
selectable states,
the
L.E.D. data
latches
are
updated
by
placing data
on the
CMOS
Data Bus
(See Fig.
3'46),
f
irstly
to
M8 and M5
(enabled
from XKD
SPl
l
and 'clocking'
from the
CMOS
CLK line
(J2-6),
secondly
to
M12
and
M11,
then M9
and
finallY M6 and M4'
The
output of the
L.E.D. latches
provide the
signals
to the
bases
of the
L.E.D. drive
transistors,
switching them
on
or
off
as
required.
M9
MAN
RATIO
HOLD
M6/M4
AUTO
10s¿
.1
1
10
100
1
000
1oMo
M8/M5
DC
kç¿
INPUT
ZERO
INPUT
F
I
LTER
KEYBOARD
I
AC
M12/M11
dB
SPEC
TEST
A_B
MIN
MAX
RESET
CMOS
DATA
LINE
cDo
cDl
cD2
CD3
cD4
cD5
cD6
cD7
F|G.3.46
CMOS DATA BUS:
LED-SELECT
cODlNc