디지탈 시스템 설계

Digital-to-Analog (D/A) Conversion

• Binary-Weighted-Input DAC

- +

8R R

_f

4R

2R

R 2

⁰

2

²

2

¹

2

³

• R/2R Ladder DAC

- +

R

_f

2

⁰

2

¹

2

²

2

³

R

2R R

2R R

2R 2R

2R

Analog-to-Digital (A/D) Conversion

• Flash (Simultaneous) ADC

R

- + R

- R +

- R +

+- R

- R +

- R +

- R +

7 6 5 4 3 2 1

0 EN

1 2 4

D₀ D₁ D₂

parallel binary output priority

encoder analog

input

comparators +V_ref

sampling pulses

• Digital-Ramp ADC

counter

latch analog

input

clock

comparator

EN C R

digital output DAC

t V

• Tracking ADC

analog input

counter C

UP clock

comparator

digital output DAC

DOWN UP/DOWN

t V

• Single-Slope ADC

analog input

clock

comparator

control logic

counter

latches EN

C R

reset

digital output ramp

generator t

V

• Dual-Slope ADC

analog input (V_in)

-V_ref

R

C

clock

comparator

control logic

counter

latches EN

C R

integrator (ramp generator)

switch control

digital output t

variable slope V_L∝V_in

0

n t=n

-V_L

• Dual-Slope ADC

analog input (V_in)

-V_ref

R

C

clock

comparator

control logic

counter

latches EN

C R

integrator (ramp generator)

switch control 0 t

fixed slope variable

slope

n t=n

V_L∝V_in

T∝V_in

-V_L

V

_L

∝n(V

_in

/R)/C

T∝CV

_L

/(V

_ref

/R)∝nV

_in

/V

_ref

• Successive-Approximation ADC

• Successive-Approximation ADC

Internal System Interfacing

• Basic Multiplexed Buses

Microprocessor RAM ROM I/O Interface

Bus

• PC Bus Architecture

CPU

North Bridge

Main Memory

LAN South

Bridge

AGP Bus Memory Bus

PCI Bus

SCSI

Graphics Adaptor

USB

PCI Bus slots

• PCI (Peripheral Component Interconnect) Bus

PCI Master Device

AD[31:0]

C/BE#[3:0]

AD[63:32]

C/BE#[7:4]

PAR PAR64

FRAME# REQ64#

TRDY# ACK64#

IRDY LOCK#

STOP#

TDI DEVSEL#

TDO IDSEL

TCK REQ#

TMS GNT#

TRST#

CLK

INTA#

RST#

INTB#

PERR#

INTC#

SERR#

INTD#

PCI Target Device

AD[31:0]

C/BE#[3:0]

AD[63:32]

C/BE#[7:4]

PAR PAR64

FRAME# REQ64#

TRDY# ACK64#

IRDY LOCK#

STOP#

DEVSEL# TDI

TDO IDSEL

TCK TMS TRST#

CLK

INTA#

RST#

INTB#

PERR#

INTC#

SERR#

INTD#

SBO#

SDONE

• PCI (Peripheral Component Interconnect) Bus

• RS-232C Serial Interface

DTE DCE

Data Carrier Detect (DCD) Receive Data (RD) Transmit Data (TD) Data Terminal Ready (DTR)

Signal Ground Data Set Ready (DSR) Request To Send (RTS) Clear To Send (CTS)

1 2 3 4 5 6 7 8

9 Ring Indicator (RI)

• USB (Universal Serial Bus)

– Replacement to the RS-232 serial interface

– Higher bandwidth up to 12 Mbps (480Mbps for USB2.0) – Ability to chain serial devices to one port

– Token packet, data packet, and handshake packet

V

_BUS

(5V)

GND D+

D- V

_BUS

GND D+

D-