MC68HC705V12CFN MOTOROLA [Motorola, Inc], MC68HC705V12CFN Datasheet - Page 132

• Manufacturer Part Number: MC68HC705V12CFN
• Description: The Motorola microcontroller
• Manufacturer: MOTOROLA [Motorola, Inc]

Analog-to-Digital (A/D) Converter
13.3 Analog Section
13.3.1 Ratiometric Conversion
13.3.2 V
13.3.3 Accuracy and Precision
13.3.4 Conversion Process
Advance Information
132
REFH
and V
REFL
This subsection describes the analog section.
The A/D is ratiometric, with two dedicated pins supplying the reference
voltages (V
to $FF (full scale) and an input voltage equal to V
An input voltage greater than V
indication. For ratiometric conversions, the source of each analog input
should use V
The reference supply for the A/D is two dedicated pins rather than being
driven by the system power supply lines. The voltage drops in the
bonding wires of the heavily loaded system power pins would degrade
the accuracy of the A/D conversion. V
voltage between V
however, the accuracy of conversions is tested and guaranteed only for
V
The 8-bit conversions shall be accurate to within
(LSB) including quantization.
The A/D reference inputs are applied to a precision internal
digital-to-analog (D/A) converter. Control logic drives this D/A and the
analog output is compared successively to the selected analog input
which was sampled at the beginning of the conversion time. The
conversion process is monotonic and has no missing codes.
REFL
= V
Analog-to-Digital (A/D) Converter
SSA
REFH
REFH
and V
and V
as the supply voltage and be referenced to V
SSA
REFH
REFL
and V
= V
). An input voltage equal to V
CCA
CCA
REFH
, as long asV
.
will convert to $FF with no overflow
REFH
and V
REFH
MC68HC705V12
REFL
REFL
1 least significant bit
> V
converts to $00.
can be any
REFL
REFH
;
MOTOROLA
converts
—
REFL
Rev. 3.0
.