nonverter to BCD

[justas12]

hi, i need to make a circuit, where 7-segments bin code is converted to bcd code, using CMOS.And circuit shoud have EI (enable input). I really need help.please

 

[ericgibbs]

hi, i need to make a circuit, where 7-segments bin code is converted to bcd code, using CMOS.And circuit shoud have EI (enable input). I really need help.please

hi,
Look for a 74C915 datasheet, it old.

 

[justas12]

thanks, but firstly, i need to make the circuit using logic elements.

 

[ericgibbs]

thanks, but firstly, i need to make the circuit using logic elements.

I see.!

Is this college work.?
Can you post the circuit you have drawn, so that we can check what you have done.?

 

[justas12]

yes it is work for my studies. i don't have what to show now, because i dont know how to start this job. is there any algorithm to make meaning table?

 

[ericgibbs]

yes it is work for my studies. i don't have what to show now, because i dont know how to start this job. is there any algorithm to make meaning table?

hi,
The 7 segments of a display are 'named' a,b,c,d,e,f,g.
The 'a' seg is the top segment, then counting clockwise b,c,d,e,f.... the g seg is the centre segment.

So write out 10 columns of 7 segments showing when the seg is lit as a '1' and not lit as a '0'.

So start your columns at column "0" BCD
this one will be the BCD number zero "0", the next column will be "1" and so on.

    "0"  "1"   "2"  "3" ... so on to "9"
a   1     0
b   1     1
c   1     1
d   1     0
e   1     0
f   1     0
g   0     0

Do you follow this part, so far.?

 

[justas12]

but 7segments binary code, have 128 meanings.am i right?.....2^7=128...

 

[ericgibbs]

but 7segments binary code, have 128 meanings.am i right?.....2^7=128...

hi,
It is not binary, if it was you would be correct.

Its a 7 segment code, look at these images.

OK.?

EDIT: are you confusing 'segments' with 'bits'.???

 

[ericgibbs]

hi,
OR is this what you are trying to do.

 

[justas12]

i need to do this:

input output
1 0000001 to 0001
......... ...............
128 1000000 to 0001 0010 1000

 

[ericgibbs]

i need to do this:

input output
1 0000001 to 0001
......... ...............
128 1000000 to 0001 0010 1000

hi,
So its the last block diagram I posted: 7 bit binary to 3 digit BCD conversion.

When you said segments in your first post I read it as a 7 segment [LED display] to BCD... they used to make an ic to do just that.!

Have you SEARCHED this forum for binary to BCD .?

EDIT: this is one thread asking the same question.
https://www.electro-tech-online.com/threads/binary-to-bcd-converter.38418/

 

[justas12]

i think, that ERICGIBBS shown circuit is what i need

 

[justas12]

yes i read forum...and i need to this using logic elements...shoud i write all 128 binary meanings? what should i do next?

 

[ericgibbs]

yes i read forum...and i need to this using logic elements...shoud i write all 128 binary meanings? what should i do next?

hi,
You will find using simple logic elements that configuring a 7 bit binary to 3 digit BCD is quite difficult.
I dont think you writing all the 0 to 127 binary/bcd's will be helpful.

Who has set you this problem.?

Look thru this link.
**broken link removed**

 

[justas12]

i saw this algorithm yesterday...but i didn't understant how does it works.. maybe, because of my bad english..can you a little explain and i will try to make similiar table..?

 

[blueroomelectronics]

What algorithm? Why not use a microcontroller?

 

[justas12]

i cant use microcontroler, because my task is tu make circuit using CMOS.

 

[blueroomelectronics]

Of course it's a school assignment. Can you use the CD4511 ?

 

[ericgibbs]

i cant use microcontroler, because my task is tu make circuit using CMOS.

hi,
What you have to do is to make 7 of the "C" modules, all the "C" modules are exactly the same. See image #1.
Look at the module truth table, this is the logic block you have to design, its not easy.

When you have the 7 "C" modules connect them as image #2.

 

[blueroomelectronics]

I hope the OP doesn't actually have to build the thing.