Philips PM2521 Service Manual page 50

51
52 V153
Control outputs
Control of the reed relays used for range changing, function switching, etc.
is
achieved
by
the
RELAY
FET
CONTROL
interface circuit
D1908 (SAA1060). The
circuit
is
software controlled
from
the
/xP
by
the
DATA
signal
P20', the
CLOCK
input P21' and the enable
signal P1
1
(DLEN4).
In the
bus
control circuit of
D1908, the data
is
checked
for
word
length (17 bits
+
leading zero) to establish
whether
it is
valid data and not interference. The
serial
data
is
fed to
a 17-bit shift register
where
it is
loaded
into a 16-bit latch B (there are
two
latches,
A
is
not used
in this application).
From
here
it is
switched directly
in parallel
form
to the appropriate outputs for relay control. See
Fig. 37.
OUTPUTS SAA1060
BIT
NO
B7 B6 B5 B4 B3 B2
B1
BO B7 B6 B5 B4 B3 B2
B1 BO
PIN
NO
1
3 11 12 10 2 22 18 13 16 20 23 24 21 17 14
SIGNALS REA REC REN RED RNGD REB RED RNGB RNGE REE REP REM RNGC RNGA REQ
RANGE
200mV
.-
1 1
0
1
0
1
0
1
0 0
0
1
0 0
1 1
2 V.-
1
1
0
1
0
1
0
1 1
0 0
1
0 0
1 1
20 V.-
0
1
0
1
0
1
0
1 1
0 0
1
0 0
1 1
200 V.-
1 1
0
1
0 0 0
1 1
0 0
1
0 0
1 1
2000
V.-.:
1
0 0
1
0
1 1 1 1
0
0
1
0 0
1 1
200mV~
1 1
0
1
0
1
0
1 1
0
0 0 0
0
0 0
2
V~
1 1
0
1
0
1
0
1 1
0 0 0 0 0
1
0
20
V~
0
1
0
1
0
1
0
1 1
0
0 0 0
0
1
0
200
V~
1 1
0
1
0 0 0
1
1
0 0 0 0 0
1
0
2000
V~
1
0 0
1
0
1 1 1 1
0
0
0
0 0
1
0
200
n
1 1 1 1
0
1
0
1
0
1
0
1
0 0
1 1
2Kfi
1 1 1 1
0
1
0
1
1
1
0
1
0 0
1 1
20KS2
1 1 1 1
0
1
0
1 1
0 0
1
0 0
1 1
200KJ2
1 1 1 1
0
1
0
1
1
0 0
1
0
1 1 1
2MJ2
1 1 1
0
1 1
0
1 1
0 0
1
0
0
1 1
20IVIJ2
1 1 1
0
1
1
0
1
1
0 0
1
0
1 1 1
2 /xA.t:
1 1
0
1
0 0
1
0
1
0 0
1
0 0
1 1
20 /xA
.-
1
0 0
1
0
1 1 1
0 0 0
1
0 0
1 1
200 mA .-
1
0 0
1
0
1 1
1 1
0 0
1
0 0
1 1
2mA
.t: 1 1
0
1
0 0 0
1
0 0 0
1
0 0
1
1
20mA
.t:
1 1
0
1
0 0 0
1 1
0 0
1
0 0
1 1
200m
A.
t: 1 1
0
1
0 0
1
0 0 0 0
1
0 0
1 1
2 A.-
1 1
0
1
0 0
1
0
1
0 0
1
0 0
1 1
20 A.-
1
0 0
1
0
1 1 1
0 0 0
1
0 0
1 1
2axA~
1 1
0
1
0 0
1
0
1
0 0 0 0 0
1
0
20^A~
1
0
0
1
0
1 1 1 1
0 0 0 0 0 0 0
200
mA~
1
0 0
1
0
1 1 1 1
0 0 0 0 0
1
0
2mA~
1 1
0
1
0 0
0
1 1
0 0 0 0 0 0 0
20mA~
1
1
0
1
0 0 0
1 1
0 0 0 0
0
1
0
200mA~
1 1
0
1
0 0
1
0
1
0 0 0 0 0
0 0
2
A~
1 1
0
1
0 0
1
0
1
0 0 0 0 0
1
0
20
A~
1
0 0
1
0
1 1 1 1
0 0 0 0 0 0
0