HD404849 Datasheet, PDF (92/125 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404849 Series
A/D Converter
The MCU has a built-in A/D converter that uses successive approximations with a resistor ladder. It can
measure eight analog inputs with 8-bit resolution. As shown in the block diagram of figure 77, the A/D
converter has a 4-bit A/D mode register, a 4-bit plus 4-bit A/D data register, a 1-bit A/D start flag, and a 1-
bit A/D current off flag.
AN₀
AN₁
AN₂
AN₃
R3₀/AN₄
R3₁/AN₅
R3₂/AN₆
R3₃/AN₇
AV_CC
AV_SS
Interrupt flag
(IFAD)
Encoder
A/D data
register
(ADRU, ADRL)
3
+
COMP
–
A/D mode
register
(AMR)
A/D control
logic
Conversion time control
Reference
voltage
A/D start flag
(ADSF)
Reference voltage control
D/A
HLT (1 in stop, watch, and
subactive modes)
A/D current
off flag
(IAOF)
Figure 77 Block Diagram of A/D Converter
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