[moved] 8051 counter to count over 255

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wajid ali khan

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Is there anyone who could help me design counter counting over 255 in mod2 of 8051 counter....
.thanks in advance
:sad:
 


8051 counter to count over 255

plz help me... i design a counter in 8051 that can count upto 255 in mod1 and also display upto 255 on 7segment displays ..after 255 it again starts counting from 001 so how should i combine TH0 with TL0
to get over 255.....
thanks in advance
:sad:
 

Re: 8051 counter to count over 255

wajid ali khan said:
plz help me... i design a counter in 8051 that can count upto 255 in mod1 and also display upto 255 on 7segment displays ..after 255 it again starts counting from 001 so how should i combine TH0 with TL0
to get over 255.....
thanks in advance
:sad:
Click to expand...

post your code here to help you better
 

Re: 8051 counter to count over 255

Code ASM - [expand]
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ORG 00H
MOV TMOD,#05H
MOV TL0,#00H
MOV TH0,#00H
SETB P3.4
MOV P1,#00H
 
SETB TR0
 
NEXT:MOV A,TL0
 
CJNE A,#100,GO
GO:JC TEN
 
 
MOV B,#100 ;;covert hex to decimel
DIV AB
MOV P1,A
MOV A,B
MOV B,#10
DIV AB
SWAP A
ORL A,B
MOV P2,A
SJMP HERE
 
 
TEN:;;convert hex to decimel
MOV B,#10
DIV AB
SWAP A
 ORL A,B
 MOV P2,A
 SJMP HERE
 
 
HERE:JNB TF0,NEXT
CLR TR0
CLR TF0
END
 
Last edited by a moderator:

is there any one to help me how to count over 255 in 8051 counter..... the following code can count upto 255...
Code: 
ORG 00H
MOV TMOD,#05H
MOV TL0,#00H
MOV TH0,#00H
SETB P3.4
MOV P1,#00H
 
SETB TR0
 
NEXT:MOV A,TL0
 
CJNE A,#100,GO
GO:JC TEN
 
 
MOV B,#100 ;;covert hex to decimel
DIV AB
MOV P1,A
MOV A,B
MOV B,#10
DIV AB
SWAP A
ORL A,B
MOV P2,A
SJMP HERE
 
 
TEN:;;convert hex to decimel
MOV B,#10
DIV AB
SWAP A
 ORL A,B
 MOV P2,A
 SJMP HERE
 
 
HERE:JNB TF0,NEXT
CLR TR0
CLR TF0
END
 

you can do by declaring one variable which count increment every time your timer overflows. see the below attached example
 

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ud23 said:
you can do by declaring one variable which count increment every time your timer overflows. see the below attached example
Click to expand...

i am giving output to 7 segment display and the one u(ud23) mentioned is about lcd.
i m giving output from the accumulator to ports and accumulator can keep maxmum upto 255....
 

Code ASM - [expand]
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; Note: a logic 0 lights a display segment.
 
start:
        SETB P3.3               ; |
        SETB P3.4               ; | enable display 3
        MOV P1, #11111001B      ; put pattern for 1 on display
        CALL delay
        CLR P3.3                ; enable display 2
        MOV P1, #10100100B      ; put pattern for 2 on display
        CALL delay
        CLR P3.4                ; |
        SETB P3.3               ; | enable display 1
        MOV P1, #10110000B      ; put pattern for 3 on display
        CALL delay
        CLR P3.3                ; enable display 0
        MOV P1, #10011001B      ; put pattern for 4 on display
        CALL delay
        JMP start               ; jump back to start
 
; a crude delay
delay:
        MOV R0, #200
        DJNZ R0, $
        RET


this is basic code for display 4 7 segment in multiplexing

for converting two byte in single 16 bit
Code ASM - [expand]
1

sixteenBitNumber = (upperByte<<8) | lowerByte;


for storing 16bit you can use dptr reg
 
Last edited:

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