E202075_HD404889 Datasheet, PDF (132/202 Pages) Renesas Technology Corp – Low-Voltage AS Microcomputers with On-Chip LCD Circuit

HD404889/HD404899/HD404878/HD404868 Series
A/D Converter
HD404899/HD404868 Series
The MCU has a built-in successive approximation type A/D converter using a resistance ladder method,
capable of digital conversion of six analog inputs (four analog inputs in the HD404868 Series) with a 10-bit
resolution. The A/D converter block diagram is shown in figures 79-1 and 79-2.
The A/D converter comprises the following four registers.
• A/D mode register (AMR: $028)
• A/D start flag (ADSF: $020,2)
• A/D data register (ADRL: $029, ADRM: $02A, ADRU: $02B)
• Module standby register 2 (MSR2: $00E)
R70/AN0
R71/AN1
R72/AN2
R73/AN3
R80/AN4
R81/AN5
AVCC
AVSS
Interrupt flag
(IFAD)
Encoder
3
A/D data
register
(ADRU, ADRM, ADRL)
+
COMP
–
A/D
control
logic
A/D mode
register
(AMR)
Conversion time control
Reference
voltage control
A/D
start flag
(ADSF)
Operating mode signal (set to 1 in
stop, watch, and subactive modes,
D/A
and during module standby)
Figure 79-1 A/D Converter Block Diagram (HD404899 Series)
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