MC80F0204 Datasheet, PDF (69/126 Pages) List of Unclassifed Manufacturers – 8-BIT SINGLE-CHIP MICROCONTROLLERS

Preliminary
MC80F0104/0204
(3) I/O operation
The analog input pins AN0 ~ AN7,AN14 and AN15 also
have function as input/output port pins. When A/D conver-
sion is performed with any pin, be sure not to execute a
PORT input instruction with the selected pin while conver-
sion is in progress, as this may reduce the conversion res-
olution.
Also, if digital pulses are applied to a pin adjacent to the
pin in the process of A/D conversion, the expected A/D
conversion value may not be obtainable due to coupling
noise. Therefore, avoid applying pulses to pins adjacent to
the pin undergoing A/D conversion.
(4) AV_DD pin input impedance
A series resistor string of approximately 5KΩ is connected
between the AV_REF pin and the V_SS pin. Therefore, if the
output impedance 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 supply voltage error
V_DD
AVREFS (PSR1.3)
ADEN
Resistor Ladder Circuit
AN0 / AV_REF
AN1
AN7
AN14
AN15
MUX
Sample & Hold
Successive
Approximation
Circuit
ADCIF
ADC
INTERRUPT
ADS[3:0] (ADCM[5:2])
ADC8
01
10-bit Mode
98
1A0D-CbiRt A(D10C-Rbit)
ADCRH
ADCRL (8-bit)
10
ADC Result Register
8-bit Mode
98
32
10-bit ADCR
00
ADCRH
ADCRL (8-bit)
10
ADC Result Register
Figure 14-3 A/D Block Diagram
Mar. 2005 Ver 0.2
65