Mikroişlemci Sistemleri

Dr. Öğr. Üyesi Hamza Osman İLHAN

2019/1-Ders 10

Ders-10 Konular• DAC (digital to analog

converter)

– Binary weighted DAC

– R/2R ladder DAC

– DAC entegresi : DAC0830

– DAC örneği

• ADC (analog to digitalconverter)

– Parallel ADC

– Ramp converter ADC

– ADC entegresi : ADC0804

– ADC örneği

DAC – digital to analog converterADC – analog to digital converter

• P dijital değerlerle çalışır, ama fiziki dünya analogtur.

• Sıcaklık, basınç, nem, hız, ses … : analog değerlerdir.

• Fiziki dünya ile P arasında etkileşim için Analog↔Dijital dönüştürücü gerekli.

DAC – digital to analog converterADC – analog to digital converter

FizikiDünya

Transducer ADC

P

FizikiDünya

Transducer DAC

Sıcaklık(analog)

Elektriksel(analog)

Elektriksel(dijital)

İşlenmiş Veri(elektriksel-dijital)

Elektriksel(analog)

Fan Hızı(analog)

Analog-Dijital SinyalZamanda Sürekli Sinyal Zamanda Ayrık Sinyal

Ge

nliğ

i Sü

rekl

i Si

nya

lG

en

liğiA

yrık

Si

nya

l

DAC (digital to analog converter)

R

2R

4R

Vout

MSB

LSB

Bin

ary

In

pu

t

4R/7

Binary weighted DAC

DAC (digital to analog converter)R/2R ladder DAC

2R

2R

2R

Vout

MSB

LSB

Bin

ary

In

pu

t

2R

2R R R

DAC0830

AD0AD7AD6

AD5

AD4

AD1

AD2

AD3

VREF8

GND3

VCC20

CS1

WR12

DI34

DI25

DI16

DI07

RFB9

GND10

IOUT111

IOUT212

DI713

DI614

DI515

DI416

XFER17

WR218

ILE(BY1/BY2)19

U11

DAC0830

U13

OP1P

-5

U13(OP)

AD[0..7]

WR

IO8

DAC0830𝑪𝑺: Chip Select (active low). The CS in combination with ILE will enable WR1.ILE: Input Latch Enable (active high). The ILE in combination with CS enables WR1.WR1: Write 1. The active low WR1 is used to load the digital input data bits (DI) into the input latch. The data in the input latch is latched when WR1 is high. To update the input latch–CS and WR1 must be low while ILE is high.WR2: Write 2 (active low). This signal, in combination with XFER, causes the 8-bit data which is available in the input latch to transfer to the DAC register.𝑿𝑭𝑬𝑹: Transfer control signal (active low). The XFER will enable WR2.𝑫𝑰𝟎-𝑫𝑰𝟕: Digital Inputs. IOUT1: DAC Current Output 1 - IOUT2: DAC Current Output 2 : to OPAMPRfb: Feedback Resistor for R-2R VREF: Reference Voltage Input. This input connects an external precision voltage source to the internal R-2R ladder. VCC - GND

DAC0830

ÖrnekMOV DX, 1000H MOV AL, 00HTEKRAR:OUT DX, ALCALL DELAYINC ALJMP TEKRAR

ADC (analog digital converter)

• Parallel ADC

ADC (analog digital converter)

• Ramp converter

ADC0804

AD7

AD0

AD1

AD2

AD3

AD4

AD5

AD6

AD7

VIN+6

VIN-7

VREF/29

CLK IN4

A GND8

RD2

WR3

INTR5

CS1

D GND10

DB7(MSB)11

DB612

DB513

DB414

DB315

DB216

DB117

DB0(LSB)18

CLK R19

VCC20

U111

ADC0804

U111(CLK IN)

12%

RV1

1k

AD[0..7]RD

WR

2 3

1

U4:A74125

IO1

IO2

ADC0804

ADC0804

ÖrnekTEKRAR:MOV DX, 0200H MOV AL, 00HOUT DX, ALMOV DX, 0400HINTR_KONTROL:IN AL, DX

TEST AL, 80HJNZ INTR_KONTROLMOV DX, 0200HIN AL, DXCALL DELAYJMP TEKRAR