M38062M3-156FP MITSUBISHI [Mitsubishi Electric Semiconductor], M38062M3-156FP Datasheet - Page 25

• Manufacturer Part Number: M38062M3-156FP
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

A-D Converter
The functional blocks of the A-D converter are described below.
[A-D conversion register]
The A-D conversion register is a read-only register that stores the
result of an A-D conversion. When reading this register during an
A-D conversion, the previous conversion result is read.
[AD/DA control register]
The AD/DA control register controls the A-D conversion process.
Bits 0 to 2 select a specific analog input pin. Bit 3 signals the
completion of an A-D conversion. The value of this bit remains at
“0” during an A-D conversion, and changes to “1” when an A-D
conversion ends. Writing “0” to this bit starts the A-D conversion.
Bits 6 and 7 are used to control the output of the D-A converter.
[Comparison voltage generator]
The comparison voltage generator divides the voltage between
AV
[Channel selector]
The channel selector selects one of the ports P6
and inputs the voltage to the comparator.
Fig. 19 Block diagram of A-D converter
SS
and V
REF
into 256, and outputs the divided voltages.
AD/DA control register
P6
P6
P6
P6
P6
P6
P6
P6
(Address 0034
0
1
2
3
4
5
6
7
/AN
/AN
/AN
/AN
/AN
/AN
/AN
/AN
1
2
3
4
5
6
7
0
16
)
0
/AN
Comparator
b7
3
0
to P6
7
/AN
A-D control circuit
Data bus
7
,
A-D conversion register
[Comparator and Control circuit]
The comparator and control circuit compares an analog input volt-
age with the comparison voltage, then stores the result in the A-D
conversion register. When an A-D conversion is complete, the
control circuit sets the AD conversion completion bit and the AD
interrupt request bit to “1”.
Note that the comparator is constructed linked to a capacitor, so
set f(X
Fig.18 Structure of AD/DA control register
Resistor ladder
V
REF
b7
IN
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
) to 500 kHz or more during an A-D conversion.
AV
8
SS
b0
MITSUBISHI MICROCOMPUTERS
(Address 0035
b0
A-D interrupt request
b2 b1 b0
AD/DA control register
(ADCON : address 0034
Analog input pin selection bits
0 0 0: P6
0 0 1: P6
0 1 0: P6
0 1 1: P6
1 0 0: P6
1 0 1: P6
1 1 0: P6
1 1 1: P6
AD conversion completion bit
0: Conversion in progress
1: Conversion completed
Not used (return "0" When read)
DA
0: DA
1: DA
DA
0: DA
1: DA
1
2
output enable bit
output enable bit
1
1
2
2
output disabled
output enabled
output disabled
output enabled
3806 Group
16
0
1
2
3
4
5
6
7
/AN
/AN
/AN
/AN
/AN
/AN
/AN
/AN
)
0
1
2
3
4
5
6
7
16
)
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