Interfacing with 8051

Microprocessors and Microcontrollers – 11EC311

Interfacing with 8051

22/09/15 8051 Interfacing - Copyleft 2

LED Interfacing

● Output Control (Pin or Port)

– SETB PX.Y– CLR PX.Y– MOV P1,A

● Input Reading (Switch)

– JB PX.Y,label– JNB PX.Y,label– MOV A,P1


7 Segment Interfacing

MOV A,#06H

MOV P1,A


LCD Interfacing


LCD Pin Description


LCD Command Codes


LCD Interfacing with 8051

P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7

8051UC

P3.0P3.1P3.2

D1D2D3D4D5D6D7


Programming LCD

● List out Inputs and Outputs from LCD Pin Diagram

● Allot Pins of 8051 to above and List down

● Programming Command Mode (Configuring LCD)

● Send a Value to Port● RS = 0● RW = 0● EN = HIGH TO LOW

● Programming Data Mode (Printing Data on LCD)

● Send a Value to Port● RS = 1● RW = 0● EN = HIGH TO LOW


Program to print KLU on LCDMOV A,#38HACALL CMDMOV A,#06HACALL CMDMOV A,#01HACALL CMDMOV A,#0EHACALL CMDMOV A,#80HACALL CMDMOV A,#'K'ACALL DATMOV A,#'L'ACALL DATMOV A,#'U'ACALL DATSJMP $


Program to print KLU on LCD(cont.)

CMD:MOV P1,ACLR P3.0CLR P3.1SETB P3.2ACALL DELAYCLR P3.2RETDAT:MOV P1,ASETB P3.0CLR P3.1SETB P3.2ACALL DELAYCLR P3.2RETEND


Example : LCD Program


LTC Programs on LCD Interfacing

● Display “CSE” on Line 1 of LCD

● Display “Hello World” on Line 2 of LCD using Indexed

● Display “Success” on Middle of Line 1 of LCD Display if a switch connected to P2.1 is Pressed


Keypad Interfacing with 8051

1422/09/15

Keypad Interfacing

1522/09/15 Sripath Roy

Keypad Interfacing Flowchart

1622/09/15 Sripath Roy

Keypad Interfacing Flowchart

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Keypad Interfacing Program

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Keypad Interfacing Program(cont.)

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Keypad Interfacing Program(cont.)

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Analog to Digital Converter(ADC) Interfacing With 8051

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Analog to Digital Convereter

● Sensors takes the environmental change and converts into Analog Electrical Signal

● Microcontroller Understand only Digital Logic

● ADC Converts Analog Signal to Digital Signal

● Voltage is Coverted into Bits of Data

● High the resolution of ADC more the data samples

● 8 Bit ADC = 256 Samples

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ADC0804 Interfacing Diagram

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ADC0804 Pin Description

● WR● Start of Conversion (O/P for 8051)● Low to High Transaction● Converts Analog Input into 8 bit Digital

● INTR● End of Conversion(I/P for 8051)● Active Low

● RD● Output Enable (I/P for 8051)● To get the 8-bit data from ADC out of D0-D7 Lines


ADC0804 Timing Diagram


Program for ADC0804

RD BIT P2.5WR BIT P2.6INTR BIT P2.7MYDATA EQU P1MOV P1,#0FFHSETB INTRCLR WR

SETB WRHERE: JB INTR, HERECLR RDMOV A,MYDATA

SETB RDSJMP BACK


Digital to Analog(DAC) Interfacing with 8051


Digital to Analog(DAC Converter)

● Converts Digital Signal to Analog

● Binary Data of n-bit into Voltages

● To control Analog Devices

● Example : DC Motor Speed Control etc


DAC0808 Interfacing Diagram


Generation of Square Wave using DAC0808

BACK:

MOV A,#0FFH

MOV P1,A

ACALL DELAY

MOV A,#00H

MOV P1,A

ACALL DELAY

SJMP BACK

END


Generation of Triangular Wave using DAC0808

BACK:MOV A,#00H

INCRE:MOV P1,A

INC A

CJNE A,#0FFH,INCRE

DECRE:MOV P1,A

DEC A

CJNE A,#00H,DECRE

SJMP BACK

END


Generation of Sawtooth Wave using DAC0808

BACK:MOV A,#00H

INCRE:MOV P1,A

INC A

CJNE A,#0FFH,INCRE

SJMP BACK

END


Generation of Step Wave using DAC0808

BACK:MOV A,#00H

INCRE:MOV P1,A

ADD A,#51D

ACALL DELAY

CJNE A,#255D,INCRE

DECRE:MOV P1,A

SUBB A,#55D

ACALL DELAY

CJNE A,#00D,DECRE

SJMP BACK

END


Stepper Motor Interfacing with 8051


Stepper Motor

● Rotor – Permanent Magnet

● Stator – 4 Windings

● Rotation of Current in Windings

Rotates the Motor

● 4 Phase Stepper Motor

● Poles or Teeth changes in Stator

● Step Angle(in Degrees) = 360/no.of Teeth

● Ex: Disk Drives, Dot Matrix Printers, Robots

● Working of Stepper Motor - Video


Normal 4-Step Sequence

CLOCKWISE STEP WINDING A WINDING B WINDING C WINDING D COUNTER CLOCKWISE

1 1 1 0 0

2 0 1 1 0

3 0 0 1 1

4 1 0 0 1


Half Step 8-Step Sequence


1 1 0 0 1

2 1 0 0 0

3 1 1 0 0

4 0 1 0 0

5 0 1 1 0

6 0 0 1 0

7 0 0 1 1

8 0 0 0 1


Wave Drive 4-Step Sequence


1 1 0 0 0

2 0 1 0 0

3 0 0 1 0

4 0 0 0 1


Stepper Motor Interfacing Diagram


Program to Rotate Stepper Motor Clock Wise

Using Wave Drive Sequence Continuously

START:

MOV A,#08H

MOV P2,A

ACALL DELAY

MOV A,#04H

MOV P2,A

ACALL DELAY

MOV A,#02H

MOV P2,A

ACALL DELAY

MOV A,#01H

MOV P2,A

ACALL DELAY

SJMP START


Program to Rotate Stepper Motor Clock Wise

Using Normal 4 Step Sequence for 50 Steps

MOV R0,#50D

MOV A,#33H

BACK:

MOV P2,A

ACALL DELAY

RR A

DJNZ R0,BACK

END


Program to Rotate Stepper Motor Anti Clock Wise

Using 200 Poles Stepper Motor for 180 Degrees MOV R0,#100D

MOV A,#33H

BACK:

MOV P2,A

ACALL DELAY

RL A

DJNZ R0,BACK

END

Calculations:Step Angle = 360/200 = 1.8Required Steps = 180/1.8 = 100


Stepper Motor LTC Programs

● Rotate the stepper Motor having 180 Poles 90 Degrees Clockwise using wave drive sequence

● Rotate the Stepper Motor having 90 Poles using Normal 4 Step Sequence 270 Degrees Anti Clock Wise and then 720 Degrees Clock Wise

● Program to run the stepper Motor Clock wise if a switch connected to P1.1 is Pressed and Anti-Clock Wise if Switch Connected to P1.0 is Pressed


References

● https://www.sites.google.com/site/sripathroykoganti/my-forms

● The 8051 Microcontroller, 3rd Edition, Ayala, CENGAGE Learning

● Microcontrollers[Theory and Applications], Ajay V Deshmukh, Tata McGraw Hill

● The 8051 Microcontroller and Embedded Systems, Muhammad Ali Mazidi, Pearson Education

https://www.sites.google.com/site/sripathroykoganti/my-forms


Thank You

Documents

Interfacing with 8051