Wednesday 28 September 2011

8253 INTERFACE


8253 INTERFACE

AIM:
                        To study 8253 Timer and verify its modes of operation
APPARATUS REQUIRED:
            1. 8085 – Micro Processor kit
            2. 8253 timer – interface board
            3. Flat ribbon cable
4. Cathode ray oscilloscope [CRO]

MODE–0   INTERRUPT ON TERMINAL COUNT:
           
            The output until be initially low after mode set operation after loading the counter the output will remain low while counting and on terminal count the output will become high until reloaded again.
Set the Channel 0 in mode 0 connect 0 to the denounce circuit and execute the following program.                                          

MODE 0
ADDRESS
OPCODE
LABEL
MENMONIC
COMMENTS
4100
3E, 30
START
MVI A, 30
CHANNEL 0
4102
D3, CE

OUT 0CEH
SS MODE 0
4104
3E, 05

MVI A, 05
LSB OFF
4106
D3, C8

OUT 0C8H
COUT OF COUNT
4108
3E, 00

MVI A, 00
MSB OF COUNT
410A
D3, C8

OUT 0C8H

410C
76

HLT

MODE1
ADDRESS
OPCODE
LABEL
MNEMONICS
COMMENTS
4100
3E, 32
START
MVI A, 32
CHANNEL 0 IN MODE1
4102
DE, CE

OUT 0CEH

4104
3E, 05

MVI A, 05

4106
D3, C8

OUT 0C8H
MSB OF COUNT
4108
3E, 00

MVI A, 00H
TRIGGER
410A
DE, C8

OUT 0C8H

41OC
D3, D0

OUT 0D0H

410E
76

HLT

MODE 2
ADDRESS
OPCODE
LABEL
MNEMONICS
COMMENTS
4100
3E, 36
START
MVI A, 36
CHANNEL 0 IN MODE3
4102
D3, CE

OUT 0CEH

4104
3E, 0A

MVI A, 0A
LSB OF COUNT
4106
D3, C8

OUT 0C8H

4108
3E, 00

MVI A, 00H
MSB OF COUNT
410A
D3, C8

OUT 0C8H

410C
76

HLT

RESULT:
            Thus the programmable timer interface is executed and the results are verified

0 comments:

Post a Comment