4507_M Datasheet, PDF (149/216 Pages) Renesas Technology Corp – 4-BIT CISC SINGLE-CHIP MICROCOMPUTER 4500 SERIES

4507 Group
APPLICATION
2.4 A/D converter
2.4 A/D converter
The 4507 Group has a 4-channel A/D converter with the 10-bit successive comparison method.
This A/D converter can also be used as a comparator to compare analog voltages input from the analog
input pin with preset values.
This section describes the related registers, application examples using the A/D converter and notes.
Figure 2.4.1 shows the A/D converter block diagram.
Register B (4)
IAP2
(P20, P21)
OP2A
(P20, P21)
P20/AIN0
P21/AIN1
P30/AIN2
P31/AIN3
IAP3
(P30, P31)
OP3A
(P30, P31)
2
Register A (4)
TAQ1
TQ1A
Q13 Q12 Q11 Q10
Instruction clock
1/6
44
44
2
TALA
8
TABAD
8
TADAB
A/D control circuit
Q13
0
1
ADF
(1)
A/D
interrupt
Comparator
1
0
Q13
Successive comparison
register (AD) (10)
10
10
DAC
operation
signal
01
Q13
Q13
8
01
1
(Note 1)
VSS
DAC
DA converter
Comparator register (8)
(Note 2)
8
VDD
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 (Q13=1).
The value of the comparator register is retained even when the mode is switched to the A/D conversion
mode (Q13=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. 2.4.1 A/D converter structure
Rev.2.01 Feb 04, 2005
REJ09B0195-0201
2-34