Philips pm2521 - 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