HMS87C1304A Datasheet, PDF (47/70 Pages) Hynix Semiconductor – CMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

HYUNDAI MicroElectronics
HMS87C1304A/HMS87C1302A
ADCM
A/D Control Register
-
-
ADEN
ADS2
ADS1
ADS0
ADST
ADSF
ADDRESS : EAH
RESET VALUE : --000001
Reserved
Analog Channel Select
000 : Channel 0 (RB0/AN0)
001 : Channel 1 (RA1/AN1)
010 : Channel 2 (RA2/AN2)
011 : Channel 3 (RA3/AN3)
100 : Channel 4 (RA4/AN4)
101 : Channel 5 (RA5/AN5)
110 : Channel 6 (RA6/AN6)
111 : Channel 7 (RA7/AN7)
A/D Status bit
0 : A/D Conversion is in process
1 : A/D Conversion is completed
A/D Start bit
1 : A/D Conversion is started
After 1 cycle, cleared to “0”
0 : Bit force to zero
A/D Enable bit
1 : A/D Conversion is enable
0 : A/D Converter module shut off
and consumes no operation current
ADCR
A/D Result Data Register
ADCR7 ADCR6 ADCR5 ADCR4 ADCR3 ADCR2 ADCR1 ADCR0
ADDRESS : EBH
RESET VALUE : Undefined
ary Figure 14-2 A/D Converter Registers
in _{ENABLE A/D CONVERTER}
Prelim ^{A/D INPUT CHANNEL SELECT}
A/D Converter Cautions
(1) Input range of AN0 to AN7
The input voltage of AN0 to AN7 should be within the
specification range. In particular, if a voltage above VDD
(or AVref) or below VSS is input (even if within the absolute max-
imum rating range), the conversion value for that channel can not
be indeterminate. The conversion values of the other channels
may also be affected.
ANALOG REFERENCE SELECT
(2) Noise countermeasures
A/D START (ADST = 1)
NOP
In order to maintain 8-bit resolution, attention must be paid to
noise on pins AVref(or VDD)and AN0 to AN7. Since the effect
increases in proportion to the output impedance of the an-
alog input source, it is recommended that a capacitor be con-
nected externally as shown in Figure 14-4 in order to reduce
noise.
ADSF = 1
NO
YES
READ ADCR
Analog
Input
100~1000pF
AN0~AN7
Figure 14-3 A/D Converter Operation Flow
Figure 14-4 Analog Input Pin Connecting Capacitor
Jan. 2001
Preliminary
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