GMS81C2012 datasheet(64/107 Pages) HYNIX

64 / 107 page

GMS81C2012/GMS81C2020

HYUNDAI MicroElectronics

MAR. 2000 Ver 1.00

Figure 13-3 A/D Converter Operation Flow

A/D Converter Cautions

(1) Input range of AN11 to AN0

The input voltage of AN11 to AN0 should be within the

specification range. In particular, if a voltage above AVDD

or below AVSS is input (even if within the absolute maximum

rating range), the conversion value for that channel can not be in-

determinate. The conversion values of the other channels may

also be affected.

(2) Noise countermeasures

In order to maintain 8-bit resolution, attention must be paid to

noise on pins AVDD and AN11 to AN0. Since

the effect in-

creases in proportion to the output impedance of the analog

input source, it is recommended that a capacitor be connected

externally as shown in Figure 13-4 in order to reduce noise.

Figure 13-4 Analog Input Pin Connecting Capacitor

(3) Pins AN11/R73 to AN8/R70 and AN7/R67 to AN0/

R60

The analog input pins AN11 to AN0 also function as input/

output port (PORT R7 and R6) pins. When A/D conver-

sion is performed with any of pins AN11 to AN0 selected,

be sure not to execute a PORT input instruction while con-

version is in progress, as this may reduce the conversion

resolution.

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) AVDD pin input impedance

A series resistor string of approximately 10K

Ω is connected be-

tween the AVDD pin and the AVSS pin.

Therefore, if the output impedance of the reference voltage

source is high, this will result in parallel connection to the

series resistor string between the AVDD pin and the AVSS pin,

and there will be a large reference voltage error.

ENABLE A/D CONVERTER

A/D START ( ADST = 1 )

NOP

ADSF = 1

A/D INPUT CHANNEL SELECT

ANALOG REFERENCE SELECT

READ ADCR

YES

AN11~AN0

100~1000pF

Analog

Input

GMS81C2012 Scheda tecnica(PDF) 64 Page - Hynix Semiconductor

GMS81C2012 Scheda tecnica(HTML) 64 Page - Hynix Semiconductor

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Scheda tecnica Scarica

Link URL