4509 Datasheet, PDF (38/142 Pages) Renesas Technology Corp – SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

4509 Group
A/D CONVERTER
The 4509 Group has a built-in A/D conversion circuit that performs
conversion by 10-bit successive comparison method. Table 11
shows the characteristics of this A/D converter. This A/D converter
can also be used as an 8-bit comparator to compare analog voltages
input from the analog input pin with preset values.
Table 11 A/D converter characteristics
Parameter
Characteristics
Conversion format Successive comparison method
Resolution
10 bits
Relative accuracy Linearity error: ±2LSB (VDD=2.7 to 5.5 V)
Differential non-linearity error: ±0.9LSB
(VDD=2.7 to 5.5 V)
Conversion speed 31 µs (f(XIN)=6 MHz, f(STCK)=f(XIN))
Analog input pin 6
P20/AIN0
P21/AIN1
P30/AIN2
P31/AIN3
D2/AIN4
D3/AIN5
Register B (4)
Register A (4)
TAQ1
TQ1A
Q13 Q12 Q11 Q10
Instruction clock
1/6
44
44
2
TALA
8
TABAD
8
TADAB
2
Q13
0
A/D control circuit
1
ADF
(1)
A/D
interrupt
Comparator
1
0
Q13
Successive comparison
register (AD) (10)
10
10
DAC
operation
signal
01
Q13
DA converter
(Note 1)
VSS
Comparator register (8)
(Note 2)
8
VDD
Q13
8
01
1
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. 31 A/D conversion circuit structure
Rev.1.02 2006.12.22 page 38 of 140
REJ03B0147-0102