Fujitsu F2MC-8L MB89620 Series Hardware Manual page 268

Clock selector
l
Selects the clock used to activate the A/D conversion or sense function when continuous
activation is enabled (ADC2: EXT = "1").
Analog channel selector
l
Selects one of the eight analog input channels.
Sample hold circuit
l
Holds the input voltage selected by the analog channel selector. The circuit samples and holds
the input voltage immediately after the A/D conversion or sense function is activated. This
allows A/D conversion (or comparison) to proceed without being affected by input voltage
fluctuation.
D/A converter
l
Generates the voltage corresponding to the value set in the ADCD register.
l Comparator
Compares the sampled and held input voltage with the output voltage of the D/A converter, and
determines which voltage is higher or lower.
Controller
l
The controller has two functions:
• For the A/D conversion function, the controller successively determines the value of each bit of
the ADCD register, starting from the most significant bit and proceeding to the least significant
bit, based on the greater-than/less-than signal from the comparator. When conversion is
complete, the circuit sets the interrupt request flag bit (ADC1: ADI).
• For the sense function, the controller sets the interrupt request flag bit (ADI) if the greater-
than/less-than signal from the comparator matches the compare condition setting bit (SIFM)
in the ADC1 register.
l ADCD register
The ADCD register has two functions:
• Stores the A/D conversion result for the A/D conversion function.
• For the sense function, the data for the voltage that is compared with the input voltage is
written to this register.
ADC1 register
l
The ADC1 register is used to enable or disable each function, select the analog input pin, check
statuses, and control interrupts.
ADC2 register
l
The ADC2 register is used to select the input clock, enable or disable interrupts, and select
functions.
n A/D Converter Power Supply Voltage
l AV
CC
The A/D converter power supply pin. Use at the same voltage as V
conversion resolution is required, take measures to ensure that the noise on V
on AV
CC
converter is not used.
AV
l
SS
The A/D converter ground pin. Use at the same voltage as V
accuracy is required, take measures to ensure that the noise on V
Connect this pin to ground (GND), even if the A/D converter is not used.
AVR
l
Reference voltage input pin for the A/D converter. The A/D converter performs 8-bit A/D
conversion between AVR and AV
Connect to AV
MB89620 series
, or use a separate power supply. Connect this pin to the power supply, even if the A/D
if the A/D converter is not used.
SS
.
SS
CHAPTER 13 A/D CONVERTER
. When high A/D
CC
is not present
CC
. When high A/D conversion
SS
is not present on AV
SS
13
.
SS
247