mc68hc908lv8 Freescale Semiconductor, Inc, mc68hc908lv8 Datasheet - Page 102

• Manufacturer Part Number: mc68hc908lv8
• Description: M68hc08 Microcontrollers 8-bit Microcontroller With Integrated Lcd Driver
• Manufacturer: Freescale Semiconductor, Inc

Analog-to-Digital Converter (ADC)
8.3 Functional Description
The ADC10 uses successive approximation to convert the input sample taken from ADVIN to a digital
representation. The approximation is taken and then rounded to the nearest 10- or 8-bit value to provide
greater accuracy and to provide a more robust mechanism for achieving the ideal code-transition voltage.
Figure 8-2
For proper conversion, the voltage on ADVIN must fall between V
or exceeds V
a 8-bit representation. If ADVIN is equal to or less than V
Input voltages between V
The ADC10 can perform an analog-to-digital conversion on one of the software selectable channels. The
output of the input multiplexer (ADVIN) is converted by a successive approximation algorithm into a 10-bit
digital result. When the conversion is completed, the result is placed in the data registers (ADRH and
ADRL). In 8-bit mode, the result is rounded to 8 bits and placed in ADRL. The conversion complete flag
is then set and an interrupt is generated if the interrupt has been enabled.
102
MCU STOP
ADHWT
V
V
REFH
REFL
AD0
ADn
shows a block diagram of the ADC10.
REFH
, the converter circuit converts the signal to $3FF for a 10-bit representation or $FF for
Input voltage must not exceed the analog supply voltages.
1
ADVIN
REFH
ADCSC
2
and V
CONTROL SEQUENCER
Figure 8-2. ADC10 Block Diagram
DATA REGISTERS ADRH:ADRL
MC68HC908LV8 Data Sheet, Rev. 2
REFL
SAR CONVERTER
are straight-line linear conversions.
NOTE
ADCK
ADCLK
CLOCK
DIVIDE
REFL
, the converter circuit converts it to $000.
COCO
AIEN
REFH
1
2
ACLK
ACLKEN
and V
REFL
BUS CLOCK
ALTERNATE CLOCK SOURCE
GENERATOR
ASYNC
CLOCK
. If ADVIN is equal to
Freescale Semiconductor
INTERRUPT