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MC68HC11PH8 Datasheet, PDF (181/264 Pages) Motorola, Inc – High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcomputer Unit | |||
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9.3
Channel assignments
The multiplexer allows the A/D converter to select one of sixteen analog signals. Eight of these
channels correspond to port E input lines to the MCU, four others are internal reference points or
test functions; the remaining four channels are reserved. Refer to Table 9-1.
Table 9-1 A/D converter channel assignments
Channel Channel Result in ADRx
number signal if MULT = 1
1
AD0
ADR1
2
AD1
ADR2
3
AD2
ADR3
4
AD3
ADR4
5
AD4
ADR1
6
AD5
ADR2
7
AD6
ADR3
8
AD7
ADR4
9Ã12
13
14
15
16
reserved
VRH(1)
VRL(1)
VRH/2(1)
reserved(1)
Ã
ADR1
ADR2
ADR3
ADR4
(1) Used for factory testing.
9
9.3.1 Single-channel operation
There are two types of single-channel operation. In the ï¬rst type (SCAN = 0), the single selected
channel is converted four consecutive times. The ï¬rst result is stored in A/D result register 1
(ADR1), and the fourth result is stored in ADR4. After the fourth conversion is complete, all
conversion activity is halted until a new conversion command is written to the ADCTL register. In
the second type of single-channel operation (SCAN = 1), conversions continue to be performed
on the selected channel with the ï¬fth conversion being stored in register ADR1 (overwriting the
ï¬rst conversion result), the sixth conversion overwriting ADR2, and so on.
MC68HC11PH8
ANALOG-TO-DIGITAL CONVERTER
TPG
MOTOROLA
9-7
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