8051 Microcontroller Projects AVR PIC Projects Tutorials Ebooks Libraries codes : Forum / topic http://www.8051projects.net/ Learn to make simple microcontroller projects, pic, 8051, avr and arm projects. download 8051 projects, tutorials, libraries, sample codes. join the microcontroller discussion forum and ask doubts regarding electronics. the best source for 8051 over internet. en-gb 2008 Rickey's World contact@nospam.com (Ajay Bhargav) contact@nospam.com (Ajay Bhargav) Wed, 07 Jan 2009 16:58:51 -0800 Wed, 07 Jan 2009 16:58:51 -0800 http://backend.userland.com/rss e107 (http://e107.org) 60 Search Search 8051 Microcontroller Projects AVR PIC Projects Tutorials Ebooks Libraries codes query http://www.8051projects.net/search.php query regarding display http://www.8051projects.net/forum-t9130.html Tue, 29 Apr 2008 17:45:19 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html
From i want understand from your posts- the ADC value is displayed in Binary format

on 8 LEDs on a port ( 33H(hex) - 00110011 (binary) - led7. ........led0 (Display on port)

1) you need a "Hex2BCD" conversion routine to display hex value into BCD on a 7

segment display For Eg: 33H is displayed as 51Decimal (BCD) on 2-digit 7seg display

after conversion.

2) if you just need the 2 digit 7 seg to display - 33, then instead of sending the

processed ADC value to Port directly store it in some Register and make a look up table

containing patterns for generating numbers from 0 to 9. i think this is where you are

getting confused, i think you are aware of the segments in a 7 seg display - seg

a,b,c,d,e,f,g,h (decimal point) - to construct 0(zero) on a 7 seg display you have to

output the port with - 11000000b or #0C0H this will mean connecting segments "g"

& "h"(Decimal point) to + 5V and grounding all other segments. now lets try displaying

"3" , so you out put -10110000b or #0B0H to the port - you ground the segs which are

to be seen( by writing zeros-0) and connect +5V to the segs which have to be hidden(by writing 1s).

i hope you are using Common Anode (LTS542) 7 seg display , if you are using Common

Cathode (LTS543) then you have to do reverse logic with the binary number you want

to display.

you draw the numbers you want to display on a paper and construct patterns 8 bit for

each number.

Apart from having lookup table ready you should also have a Compare subroutine to CJNE the value

stored in a register( ADC value which is stored) to the look up table.

for eg: 33H is 00110011b which is a packed BCD number which is made up of two

numbers - 3H and 3H after unpacking(higher nibble and lower nibble) you will get -

00000011b and 00000011 now store these two values in 2 variables say HI_Byte and

LO_Byte. now compare Hi_byte in the sub routine with the Look up table and

display1st digit , same way compare Lo_byte in the lookup table and display 2nd digit.

you may have to mutliplex the digits or use CD4511 BCD decoders for each digit

hope this will solve your problem

ho boy it's been a lengthy Post - thanks to my patience

Arun]]> contact@nospam.com (Ajay Bhargav) Thu, 01 May 2008 19:50:57 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html
Actually, u need to interface a multiplexed LED display to the uC. If u clarify the above points, i can provide u a ciruit idea about the connection.]]> contact@nospam.com (Ajay Bhargav) Tue, 29 Apr 2008 19:12:01 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html setb p2.5
setb p2.6
intr bit p2.7
setb intr
adc_port equ p1
adc_val equ 30h
voltage_val equ r3
back: clr wr
setb wr
acall conversion
read: clr rd
mov a,adc_val
setb rd
mov r3,#00h
acall data_display1
mov r3,#01h
acall data_display2
mov r3,#02h
acall data_display3
mov r3,#03h
acall data_display4
mov r3,#04h
acall data_display5
mov r3,#05h
acall data_display6
sjmp back
data_display1: mov a,#00h
conversion: mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov p1,r7
acall delay
mov p1,r6
acall delay
mov p1,r5
acall delay
ret
data_display2: mov a,#33h
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov p1,r7
acall delay
mov p1,r6
acall delay
mov p1,r5
acall delay
ret
data_display3: mov a,#67h
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov p1,r7
acall delay
mov p1,r6
acall delay
mov p1,r5
acall delay
ret
data_display4: mov a,#97h
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov p1,r7
acall delay
mov p1,r6
acall delay
mov p1,r5
acall delay
ret
data_display5: mov a,#99h
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov p1,r7
acall delay
mov p1,r6
acall delay
mov p1,r5
acall delay
ret
data_display6: mov a,#0ffh
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov p1,r7
acall delay
mov p1,r6
acall delay
mov p1,r5
acall delay
ret
delay: mov r4,#200
here: djnz r4,here
ret
end

]]> contact@nospam.com (Ajay Bhargav) Tue, 29 Apr 2008 19:48:36 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html Plz do not make multiple posts of the same topic....you have posted the same question in 3 diff. threads!!
As for your problem...you would need to display 3 digits.So you need three multiplexed 7-seg displays as pdi33 pointed out.
In multiplexing what you do is connect all the 7-seg displays in parallel,to one uc port,ie P1 in your case. Now Vcc to each display is provided by a transistor controlled by a port pin.So when the transistor connected to a particular display is switched on,only that display(out of the 3) will work.Similarly the next display will be made to turn on and the remaining will be off.When this cycle continues at a fast rate (greater than 20Hz) you get the impression that all 3 displays are on at the same time.
Look at the attached ckt.The display is a common anode one.To switch any display on you'll have to write a 0 to the particular port pin(P2.0,P2.1 or P2.2).

]]> contact@nospam.com (Ajay Bhargav) Wed, 30 Apr 2008 01:08:41 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html
Digit........ P1value(in hex)
--------------------------------
0........... C0
1........... F9
2........... A4
3........... B0
4........... 99
5........... 92
6........... 82
7........... F8
8........... 80
9........... 98
]]> contact@nospam.com (Ajay Bhargav) Wed, 30 Apr 2008 01:19:10 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html first u define a byte say digit_count = 0. then folow the following steps

step1: disable all digits (p2.0=p2.1=p2.2 = 1)
step2: fetch seven-segment code for the particular digit corresponding to digit_count.
step3: output the seven-segment code to port1
step4: enable the selected digit (p2.0/p2.1/p2.2 = 0) depending upon the digit_count.
step 5: increment the digit_count and reset it if it is > = 3.
return.

this routine should be called in the main loop and should be called continuously in real time.( rate of execution should be > 60hz. as the full display will be shown only when the routine is executed three times for the three digits.)
]]> contact@nospam.com (Ajay Bhargav) Wed, 30 Apr 2008 04:56:56 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html contact@nospam.com (Ajay Bhargav) Thu, 01 May 2008 16:21:13 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html For displaying digit '0' in the 7-seg,you have to send 'C0'.
For displaying digit '1',you have to send 'F9'.....and so on.
Read the above posts........]]> contact@nospam.com (Ajay Bhargav) Thu, 01 May 2008 17:29:22 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html contact@nospam.com (Ajay Bhargav) Thu, 01 May 2008 17:40:03 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html just convert ur binary input from the ADc into BCD and output it to port p2 and lower nibble of p3. i.e two digits on p2 and one digit on port 3.0 to p3.3.
direct_display.pdf]]> contact@nospam.com (Ajay Bhargav) Fri, 02 May 2008 05:04:46 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html contact@nospam.com (Ajay Bhargav) Mon, 05 May 2008 16:48:39 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html contact@nospam.com (Ajay Bhargav) Mon, 05 May 2008 17:18:53 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html
CODE:
setb p2.5
setb p2.6
intr bit p2.7
setb intr
adc_port equ p1
adc_val equ 30h
voltage_val equ r3
back:  clr wr
         setb wr
         acall conversion
 read:   clr rd
         mov a,adc_val
         setb rd
         mov r3,#00h
         acall data_display1
         mov r3,#01h
         acall data_display2
         mov r3,#02h
         acall data_display3
         mov r3,#03h
         acall data_display4
         mov r3,#04h
         acall data_display5
         mov r3,#05h
         acall data_display6
         sjmp back
  data_display1:  mov a,#00h
   conversion:    mov b,#0ah
                   div ab
                   mov r7,b
                   mov b,#0ah
                   div ab
                   mov r6,b
                   mov r5,a
                   mov p1,r7
                   acall delay
                   mov p1,r6
                   acall delay
                   mov p1,r5
                   acall delay
                   ret
data_display2:     mov a,#33h
                    mov b,#0ah
                    div ab
                    mov r7,b
                    mov b,#0ah
                    div ab
                    mov r6,b
                    mov r5,a
                   mov p1,r7
                    acall delay
                    mov p1,r6
                    acall delay
                    mov p1,r5
                    acall delay
                    ret
 data_display3:    mov a,#67h
                   mov b,#0ah
                   div ab
                   mov r7,b
                   mov b,#0ah
                   div ab
                   mov r6,b
                   mov r5,a
                  mov p1,r7
                   acall delay
                   mov p1,r6
                   acall delay
                   mov p1,r5
                   acall delay
                   ret
  data_display4:   mov a,#97h
                    mov b,#0ah
                    div ab
                    mov r7,b
                    mov b,#0ah
                    div ab
                    mov r6,b
                    mov r5,a
                    mov p1,r7
                    acall delay
                    mov p1,r6
                    acall delay
                    mov p1,r5
                    acall delay
                    ret
 data_display5:     mov a,#99h
                    mov b,#0ah
                    div ab
                    mov r7,b
                    mov b,#0ah
                    div ab
                    mov r6,b
                    mov r5,a
                    mov p1,r7
                    acall delay
                    mov p1,r6
                    acall delay
                    mov p1,r5
                    acall delay
                     ret
  data_display6:    mov a,#0ffh
                      mov b,#0ah
                      div ab
                      mov r7,b
                      mov b,#0ah
                      div ab
                      mov r6,b
                      mov r5,a
                     mov p1,r7
                      acall delay
                      mov p1,r6
                      acall delay
                      mov p1,r5
                      acall delay
                      ret
        delay:         mov r4,#200
        here:          djnz r4,here
                        ret
                        end                                
                                                                                                                       
                                       
]]> contact@nospam.com (Ajay Bhargav) Mon, 05 May 2008 17:35:52 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html
did you read my earlier post in this thread ? it took a lot of my time to explain the whole

concept in a simple way. Again your are back to square One and all you do is ask the same question

again and again. other members too have tried their best to explain to you the concept even with

diagrams but you don't want to learn .



Please Note: it is minimum courtesy for you to thank the members who are trying to help you before you

start your new post


Arun




]]> contact@nospam.com (Ajay Bhargav) Mon, 05 May 2008 18:23:54 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html For e.g. note the following code:
'data_display1: mov a,#00h
conversion: mov b,#0ah'
What does it exactly do? Is it the display driving routine or the ADC conversion routine .
Always define the port pins with the respective functions as it makes the code more readable for u as well as for US
Also mention whether u are using the direct display drive ( check circuit diagram posted by me in my previous post) or the multiplexed display as suggested by shashi. This is important as both methods require completely different code logic .
]]> contact@nospam.com (Ajay Bhargav) Mon, 05 May 2008 19:33:06 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html You can do it this way...

CODE:
data_display6: mov a,#0ffh
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov p1,r7
acall delay
mov p1,r6
acall delay
mov p1,r5
acall delay


change to
CODE:
data_display6: mov a,#0ffh
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov a,r7
acall disp_7seg
;mov p1,r7
acall delay
mov a,r6
acall disp_7seg
;mov p1,r6
acall delay
mov a,r5
acall disp_7seg
;mov p1,r5
acall delay


for disp_7seg subroutine,you compare the value of 'a' with 0.If they match send 'CO' to P1.If not then compare 'a' with 1 and send 'F9' if they match.Similarly proceed with other digits upto 9.

CJNE a,#0,D1
mov p1,#0C0h
D1:CJNE a,#1,D2
mov p1,#0F9h
D2:CJNE a,#2,D3
mov p1,#0A4h
.
.
.
.
ret]]> contact@nospam.com (Ajay Bhargav) Tue, 06 May 2008 04:00:09 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html


CODE:
disp_7seg:  CJNE a,#0,D1
                    mov p1,#0C0h
                    sjmp back
           
D1: CJNE a,#1,D2
        mov p1,#0F9h  
        sjmp back
           
D2:  CJNE a,#2,D3
        mov p1,#0A4h  
        sjmp back
.
.
.
.
.
back:  ret
 


Arun]]> contact@nospam.com (Ajay Bhargav) Tue, 06 May 2008 12:18:02 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html contact@nospam.com (Ajay Bhargav) Tue, 06 May 2008 13:51:56 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html setb p2.5
setb p2.6
intr bit p2.7
setb intr
adc_port equ p1
adc_val equ 30h
voltage_val equ r3
back: clr wr
setb wr
conversion: acall conversion
read: clr rd
mov a,adc_val
setb rd
mov r3,#00h
acall data_display1
mov r3,#01h
acall data_display2
mov r3,#02h
acall data_display3
mov r3,#03h
acall data_display4
mov r3,#04h
acall data_display5
mov r3,#05h
acall data_display6
sjmp back
data_display1: mov a,#00h
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov a,r7
mov p1,r7
acall disp_7segment
acall delay
mov a,r6
mov p1,r6
acall disp_7segment
acall delay
mov a,r5
mov p1,r5
acall disp_7segment
acall delay
data_display2: mov a,#33h
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov a,r7
mov p1,r7
acall disp_7segment
acall delay
mov a,r6
mov p1,r6
acall disp_7segment
acall delay
mov a,r5
mov p1,r5
acall disp_7segment
acall delay
data_display3: mov a,#67h
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov a,r7
mov p1,r7
acall disp_7segment
acall delay
mov a,r6
mov p1,r6
acall disp_7segment
acall delay
mov a,r5
mov p1,r5
acall disp_7segment
acall delay
data_display4: mov a,#99h
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov a,r7
mov p1,r7
acall disp_7segment
acall delay
mov a,r6
mov p1,r6
acall disp_7segment
acall delay
mov a,r5
mov p1,r5
acall disp_7segment
acall delay
data_display5: mov a,#97h
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov a,r7
mov p1,r7
acall disp_7segment
mov a,r6
mov p1,r6
acall disp_7segment
mov a,r5
mov p1,r5
acall disp_7segment
acall delay
data_display6: mov a,#0ffh
mov b,#0ah
div ab
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov a,r7
mov p1,r7
acall disp_7segment
mov a,r6
mov p1,r6
acall disp_7segment
mov a,r5
mov p1,r5
acall disp_7segment
acall delay
disp_7segment: cjne a,#0,d1
mov p1,#0c0h
ret
d1: cjne a,#1,d2
mov p1,#0f9h
ret
d2: cjne a,#2,d3
mov p1,#0a4h
ret
d3: cjne a,#3,d4
mov p1,#0b0h
ret
d4: cjne a,#4,d5
mov p1,#99h
ret
d5: cjne a,#5,d6
mov p1,#92h
ret
d6: cjne a,#6,d7
mov p1,#82h
ret
d7: cjne a,#7,d8
mov p1,#0f8h
ret
d8: cjne a,#8,d9
mov p1,#80h
ret
d9: cjne a,#9,d10
d10: mov p1,#98h
ret
delay: mov r4,#200
here: djnz r4,here
ret
end

thanking u,]]> contact@nospam.com (Ajay Bhargav) Wed, 07 May 2008 20:51:48 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html thanking u sir]]> contact@nospam.com (Ajay Bhargav) Wed, 07 May 2008 21:07:18 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html
CODE:
setb p2.5
setb p2.6
intr bit p2.7
setb intr
adc_port equ p1
 adc_val equ 30h
voltage_val equ r3
back: clr wr
setb wr
conversion: acall conversion
read: clr rd
mov a,adc_val
setb rd



here are the two bugs i found :

back: clr wr
setb wr
conversion: acall conversion

1) label name : back is already defined once and you are using it again in the disp_7seg routine,

in my last post i used the sjmp back ( i didn't know that back label was already used )command just to

avoid so many ret s, so the program was trying to sjmp (short jump) from disp_7seg routine to back

label in the begininng of the program which is obviously out of address range ( in some cases when you get "out

of range " error trying using LJMP command instead of SJMP)

2) conversion: acall conversion - the program counter is stuck here indefinetly


3) tip : it is a good practice to First relocate the stack pointer beyond the 4 Register Banks Address & bit addressable ram ( from 20h) in the main routine - this avoids stack overflow/over writing



you can use : MOV SP,#50H ; put this in the first line of your Main routine to relocate SP to some safe

address which you'll not be using for your variables



try these corrections and simulate


Arun





]]> contact@nospam.com (Ajay Bhargav) Thu, 08 May 2008 02:32:42 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html
data_display1: mov a,#00h
mov b,#0ah
div ab -----here acc=0 and b =0ah
mov r7,b
mov b,#0ah
div ab
mov r6,b
mov r5,a
mov a,r7
mov p1,r7 -------here r7 will always bear a value 00h

from ur code i feel that the segments of display are connected to port p1.
now in the above code there is no mention of the register r3 nor is the adc_val u have put in accumulator. So please check the logical flow of ur routine. also mention the hardware connections of the adc and display to the uC to avoid further confusion.]]> contact@nospam.com (Ajay Bhargav) Thu, 08 May 2008 00:49:25 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html CODE:
mov r6,b
mov r5,a
mov a,r7
mov p1,r7
acall disp_7segment
acall delay
mov a,r6
mov p1,r6
acall disp_7segment
acall delay
mov a,r5
mov p1,r5
acall disp_7segment
acall delay


Comment out or remove the fol. lines in the code above(as well as in all the other display routines).
1)mov p1,r7
2)mov p1,r6
3)mov p1,r5

]]> contact@nospam.com (Ajay Bhargav) Thu, 08 May 2008 03:49:24 -0700 http://www.8051projects.net/forum-t9130.html Re: query regarding display http://www.8051projects.net/forum-t9130.html contact@nospam.com (Ajay Bhargav) Thu, 08 May 2008 18:06:30 -0700 http://www.8051projects.net/forum-t9130.html