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CHAPTER 8: REGISTER-LEVEL I/O MAPS
WRITE:
CH1-CH4 These bits control the multiplexer, and they determine the channel to be
connected to the A/D input amplifier as follows:
INTE
OIP
OP1
OPO
INT4
INT2
lNTl
INTO
CH4
CH2
CH1
CHANNEL
0
0
1
1
0
2
1
3
0
4
1
5
0
6
1
7
EX1-EX4 These bits select the STA-EXg(s) multiplexer channel. (See Chapter 2 for
more details.) If the ADC-16 is not used with an STA-EX8, these bits may be used as
general purpose digital outputs.
NOTE:
To allow the input amplifier time to settle, select the channel and gain about 50
microseconds before an A/D conversion is initiated. If
you
are programming in
Interpreted
BASIC,
the software delays will more than exceed the required amplifier
settling time. However, if you are using a compiled language
or
Assembly, program a
small delay loop into the code for maximum accuracy.
8.5
CONTROL REGISTER (BASE ADDRESS +3)
O P = OverrangePolady Bit Select. If set high (l), overrange data is returned in D7 of
the
A/D
High Register @ase Address
+
0). If
this bit is cleared (0), polarity data is be
returned in D7 of the
A/D
High Register.
OPO
&
OP1
= Digital
O u t p u t .
These bits also drive ADC-16 relays RELl (OP1) and
RELO (opoj.
8 - 3
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