XC68HC05P18A Motorola, XC68HC05P18A Datasheet - Page 92

• Manufacturer Part Number: XC68HC05P18A
• Description: HCMOS Microcontroller Unit
• Manufacturer: Motorola

Analog-to-Digital (A/D) Converter
11.3 Analog Section
11.3.1 Ratiometric Conversion
11.3.2 Reference Supply Voltage (V
11.3.3 Accuracy and Precision
11.4 Conversion Process
Technical Data
92
The following paragraphs describe the operation and performance of
analog modules within the analog subsystem.
The A/D converter is ratiometric, with pin V
reference voltage. Applying an input voltage equal to V
conversion result of $FF (full scale). Applying an input voltage equal to
V
V
conversions, V
voltage being used by the analog signal being measured and be
referenced to V
The reference supply for the A/D converter shares pin PC7 with port C.
The low reference is tied to the V
voltage between V
tested and guaranteed only for V
The 8-bit conversion result is accurate to within
significant bit), including quantization; however, the accuracy of
conversions is tested and guaranteed only with external oscillator
operation.
The A/D reference inputs are applied to a precision digital-to-analog
(D/A) converter. Control logic drives the D/A and the analog output is
successively compared to the selected analog input that was sampled at
SS
REFH
produces a conversion result of $00. An input voltage greater than
converts to $FF with no overflow indication. For ratiometric
Analog-to-Digital (A/D) Converter
REFH
REFH
SS
.
SS
)
should be at the same potential as the supply
and V
DD
; however, the accuracy of conversions is
REFH
SS
pin internally. V
= V
DD
REFH
.
supplying the high
1 1/2 LSB (least
REFH
REFH
MC68HC05P18A
can be any
produces a
MOTOROLA