E202075_HD404889 Datasheet, PDF (128/202 Pages) Renesas Technology Corp – Low-Voltage AS Microcomputers with On-Chip LCD Circuit

HD404889/HD404899/HD404878/HD404868 Series
A/D Converter
HD404889 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 with an 8-bit resolution. The A/D converter block
diagram is shown in figure 73.
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: $02A, ADRU: $02B)
• Module standby register 2 (MSR2: $00E)
Note : Address $029 is a reserved register, and should not be read or written to.
R70/AN0
R71/AN1
R72/AN2
R73/AN3
R80/AN4
R81/AN5
AVCC
AVSS
Interrupt flag
(IFAD)
Encoder
3
A/D data
register
(ADRU, 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 73 A/D Converter Block Diagram
126