MC80F0304/08/16
November 4, 2011 Ver 2.12
79
may not be obtainable due to coupling noise. Therefore, avoid ap-
plying pulses to pins adjacent to the pin undergoing A/D conver-
sion.
(4) AV
DD
pin input impedance
A series resistor string of approximately 5K
Ω
is connected be-
tween the AV
REF
pin and the V
SS
pin. Therefore, if the output im-
pedance of the analog power source is high, this will result in
parallel connection to the series resistor string between the
AV
REF
pin and the V
SS
pin, and there will be a large analog sup-
ply voltage error
Figure 14-3 A/D Block Diagram
AN0
/
AV
REF
Sample & Hold
AN1
AN14
Successive
Approximation
ADCIF
ADC Result Register
ADC
INTERRUPT
MUX
Resistor Ladder Circuit
V
DD
ADS[3:0] (ADCM[5:2])
Circuit
ADEN
ADC Result Register
ADC8
0
1
2
3
8
9
0
1
ADCRL (8-bit)
10-bit ADCR
ADCRH
0 0
ADCRL (8-bit)
ADCRH
ADCR (10-bit)
8
9
10-bit ADCR
10-bit Mode
8-bit Mode
0
1
01
AN15
AVREFS (PSR1.3)
The conversion time takes 13 times of conversion source clock.
The conversion source clock should selected for the conversion
time being more than 25
μ
s