Chương 3 họ vi điều khiển 8051

Writing “1” to Output Pin P1.XD Q Clk Q Vcc LoadL1Read latch... Writing “0” to Output Pin P1.XD Q Clk Q Vcc LoadL1Read latch... MOV A,P1 external pin=High 1... MOV A,P1 external pin=Lo

CHƯƠNG 3

HỌ VI ĐiỀU KHIỂN 8051

Kiến trúc phần cứng 8051

8051 Pin Diagram

PDIP/Cerdip

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21

P2.7(A15) P2.6(A14) P2.5(A13) P2.4(A12) P2.3(A11) P2.2(A10) P2.1(A9) P2.0(A8)

8051 (8031)

Writing “1” to Output Pin P1.X

D Q Clk Q

Vcc

Load(L1)Read latch

Writing “0” to Output Pin P1.X

D Q Clk Q

Vcc

Load(L1)Read latch

Reading “1” at Input Pin

D Q Clk Q

Vcc

Load(L1)Read latch

8051 IC

2 MOV A,P1 external pin=High

1 write a 1 to the pin

Reading “0” at Input Pin

D Q Clk Q

Vcc

Load(L1)Read latch

8051 IC

2 MOV A,P1 external pin=Low

1 write a 1 to the pin

Instructions For Reading an Input Port

Mnemonics Examples Description

MOV A,PX MOV A,P2 Bring into A the data at P2 pins

JNB PX.Y, JNB P2.1,TARGET Jump if pin P2.1 is low

JB PX.Y, JB P1.3,TARGET Jump if pin P1.3 is high

MOV C,PX.Y MOV C,P2.4 Copy status of pin P2.4 to CY

• Following are instructions for reading external pins of ports:

Figure C-17 Reading the Latch

D Q Clk Q

Vcc

Load(L1)Read latch

1 Read pin=0 Read latch=1

Write to latch=0 (Assume

P1.X=0 initially)

1

TB1

TB2

3 write result to latch

Read pin=0 Read

latch=0 Write to

latch=1

1 0

Read-Modify-Write Instructions

Example Mnemonics

CLR P1.3 CLR PX.Y

MOV P1.2,C MOV PX.Y,C

DJNZ P1,TARGET DJNZ PX, TARGET

INC P1 INC

CPL P1.2 CPL

JBC P1.1, TARGET JBC PX.Y, TARGET

XRL P1,A XRL

ORL P1,A ORL

ANL P1,A ANL

DEC P1 DEC

A Pin of Port 0

8051 IC

D Q Clk Q

TB1TB2

 P1.x

Port 0 with Pull-Up Resistors

P0.0 P0.1 P0.2 P0.3 P0.4 P0.5 P0.6 P0.7

D0 D7

P2.0

P2.7

A8 A12

OE OC

Address

D0 D7

P2.0

P2.7

A8 A12

OE OC

EA

G

2 74373 latches the address and send to ROM

Address

3 ROM send the instruction back

• Định địa chỉ tương đối

• Định địa chỉ tuyệt đối

• Định địa chỉ dài

• Định địa chỉ chỉ số

– Bảng tra trên ROM

• Nhóm lệnh với biến Boolean

• Nhóm lệnh rẽ nhánh chương trình

3.5 Bộ định thì

(Timer)

TH0

AGAIN : MOV A, TH1

MOV R6, TL1 CJNE A, TH1, AGAIN

3.6 Cổng nối tiếp (Serial port)

MOV A, PCON

SETB ACC.7

3.7 Ngắt (Interrupt)