M34512M2 Datasheet, PDF (32/80 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

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MITSUBISHI MICROCOMPUTERS
4512 Group
SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER
A-D CONVERTER
The 4512 Group has a built-in A-D conversion circuit that performs
conversion by 10-bit successive comparison method. Table 14
shows the characteristics of this A-D converter. This A-D converter
can also be used as an 8-bit comparator to compare analog volt-
ages input from the analog input pin with preset values.
Table 14 A-D converter characteristics
Parameter
Characteristics
Conversion format Successive comparison method
Resolution
10 bits
Relative accuracy Linearity error: ±2LSB
Non-linearity error: ±0.9LSB
Conversion speed 46.5 µs (High-speed mode at 4.0 MHz
oscillation frequency)
Analog input pin
4
Register B (4)
TAQ 2
TQ 2A
TAQ 1
TQ 1A
Q23 Q22 Q21 Q20 Q13 Q12 Q11 Q10
Register A (4)
44
44
2
TALA
Instruction clock
1/ 6
8
TABAD
8
TAD AB
3
Q23
0
A-D control circuit
1
ADF
(1)
A-D
interrupt
AIN0
Comparator
1
Successive comparison
AIN1
0
register (AD) (10)
Q23
Q23
10
10
8
AIN2
AIN3
DAC
operation
signal
01
Q23
01
1
8
DA converter
(Note 1)
VDD
VSS
Comparator register (8)
(Note 2)
88
Notes 1: This switch is turned ON only when A-D converter is operating and generates the comparison voltage.
2: Writing/reading data to the comparator register is possible only in the comparator mode (Q23=1).
The value of the comparator register is retained even when the mode is switched to the A-D conversion
mode (Q23=0) because it is separated from the successive comparison register (AD). Also, the resolution in
the comparator mode is 8 bits because the comparator register consists of 8 bits.
Fig. 26 A-D conversion circuit structure
32