Chương 2 :Giao thức ghép nối ppsx

P&I-Ch2: Protocols 1

ch. 2 giao thøc ghÐp nèi

(Interfacing Protocols)

Bao gåm:

- Giao thøc ghÐp nèi

- §Æc ®iÓm lËp tr×nh I/O

P&I-Ch2: Protocols 2

2.1. Interface Protocols:

• K/n: Lµ c¸c qui ®Þnh:

– Signals

– Data format

– Rate

– Error detection & correction

– Command & Response set

– Scenario (kÞch b¶n)

ISO 7 layer Model (Ref. Computer networks) Cã thÓ ph©n chia thµnh 2 nhãm chÝnh:

• Transport-Oriented Protocols (1..4) (!!!)

– PhysicAL (wire, cable, connector, port), DataLink (CRC,

CS, Token), NetWork (Comm. 2 networks ), Transport (Err-protected raw infor),

• Application-Oriented Protocols (5..7) :

– Session (Opening, End), Presentation (Common

Language) vµ Application (Read/Write, Start/Stop, FileTransfer)

P&I-Ch2: Protocols 3

2.1. Interface Protocols: 2.1.1. Signals:

Khi thiÕt kÕ, x©y dùng ghÐp nèi m¸y tÝnh, cÇn chó ý

®Æc biÖt tíi tÝn hiÖu theo c¸c yªu cÇu:

• H¬n 1 thiÕt bÞ? => bus/m¹ng hay kh«ng ? => dïng bit

(tr

−êng) ®Þa chØ.

• NÕu dïng bus => Standard bus hay kh«ng?

IDE vμ LPT-mode 0 cables lμ bus? t¹i sao?

• Data: Xa /gÇn, nhanh/chËm => Serial vs Parallel

• Xa: Daisy chain cho t/h hoÆc nguån cÊp...

• C¸c tÝn hiÖu ®iÒu khiÓn vµ tr¹ng th¸i:

• Control signals

• Status signals

• Handshaking signals - b

ắt tay