MC68HC711G5 MOTOROLA [Motorola, Inc], MC68HC711G5 Datasheet - Page 114

• Manufacturer Part Number: MC68HC711G5
• Description: High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcontroller
• Manufacturer: MOTOROLA [Motorola, Inc]

The A/D converter is ratiometric. An input voltage equal to V
an input voltage equal to V
$FFC0 with no overflow indication. Note that the six least significant bits always read zero. For
ratiometric conversions, the source of each analog input should use V
be referenced to V
The A/D reference inputs are applied to a precision internal digital-to-analog converter. Control logic
drives this D/A and the analog output is successively compared to the selected analog input which
was sampled at the beginning of the conversion time. The conversion process is monotonic with no
missing codes.
A multiplexer allows the single A/D converter to select one of sixteen analog signals. Eight of these
channels are supported on the Port E input pins. Of the eight other channels, four are reserved for
future use and four are for internal reference points and testing purposes. Table 9-1 shows the
signals selected by the channel select bits (CD, CC, CB, CA) in the ADCTL register. All “reserved”
channels are connected to V
MOTOROLA
9-2
9.1
9.2
CONVERSION PROCESS
CHANNEL ASSIGNMENTS
CD
0
0
0
0
0
0
0
0
1
1
1
1
1
CC
CONV8 = 0
rl
0
0
0
0
1
1
1
1
0
1
1
1
1
.
rl
CB
X
0
0
1
1
0
0
1
1
0
0
1
1
rl
converts to $0000. An input voltage greater than V
.
Table 9-1. Channel Assignments
ANALOG-TO-DIGITAL CONVERTER
CA
X
0
1
0
1
0
1
0
1
0
1
0
1
Channel Signal
Test (reserved)
AN1 (PE0)
AN2 (PE1)
AN3 (PE2)
AN4 (PE3)
AN5 (PE4)
AN6 (PE5)
AN7 (PE6)
AN8 (PE7)
reserved
V /2
V
V
rh
rh
rl
rh
converts to $FFC0 (full scale) and
MULT = 1
Result in register if
ADR5
ADR6
ADR7
ADR8
ADR5
ADR6
ADR7
ADR8
ADR5
ADR6
ADR7
ADR8
rh
as the supply voltage and
MULT = 0
ADR5 – 8
ADR5 – 8
ADR5 – 8
ADR5 – 8
ADR5 – 8
ADR5 – 8
ADR5 – 8
ADR5 – 8
ADR5 – 8
ADR5 – 8
ADR5 – 8
ADR5 – 8
rh
will convert to
MC68HC11G5