# conversion of decimal to hexa......

Discussion in 'The Projects Forum' started by daveglion, Jul 30, 2007.

1. ### daveglion Thread Starter Member

Jul 1, 2007
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pls post an schematic diagram of that conversion.....using logic gates and to show the outputs on a 7 segment display....
I just finished it but i used 14 IC's,
Any help to make it in a simle way... i mean in a small number of Ic's...

2. ### Papabravo Expert

Feb 24, 2006
10,340
1,850
How many decimal digits? How many hexadecimal digits? Could you possibly post your result and give us something to work with.

BTW I am by no means convinced that it can be done with fewer chips unless one of them is a microcontroller.

3. ### daveglion Thread Starter Member

Jul 1, 2007
21
0
I used OR logic gates (7432) and inverter (7404) for that circuit....It is composed of 16 inputs(for the swithes) as for a decimal then converted to hexadecimal 8 outputs(showed in 7 segment display)
I am thinking if i can minimize the numbers of IC's i used using other logic IC's..... I have to make yhe circuit in just 2 breadboards that's why i need it.....
Tnx for replies..........

4. ### Papabravo Expert

Feb 24, 2006
10,340
1,850
Unfortuneately your response lacks the clarity I was hoping for. Are the 16 inputs bits or decimal digits? Are the 8 outputs bits or hexadecimal digits. Although you used the singular, 7 segment display, I think you must have more than one. Without a diagram or a description with greater clarity and precision I don't see how I can help you.

Regardless, a microcontroller or a programmable gate array the only rational ways to reduce the chip count. Fourteen packages sounds like a win for MSI logic.

5. ### lightingman Senior Member

Apr 19, 2007
374
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I would just do it with an EPROM....Daniel.

6. ### techroomt Senior Member

May 19, 2004
198
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i am thinking that 16 decimal inputs (switches) can be converted to single hexadecimal digit, unless you were needing to use zero. can you describe your "operational criteria" a little more?

7. ### Papabravo Expert

Feb 24, 2006
10,340
1,850
I would not call a switch a decimal input, I'd call it a binary input. If you mean that each switch stands for a different hexidecimal digit and you want to decode one of sixteen inputs into a single hexadecimal digit then that is a bit clearer.

8. ### techroomt Senior Member

May 19, 2004
198
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that's exactly what i was meaning to say, but i was implying that each switch represented a decimal input, not hexadecimal. but we are only stabbing at daveglion's intentions

9. ### daveglion Thread Starter Member

Jul 1, 2007
21
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yeah that's right... each switches are inputs of decimals....and to show it's conversion to hexa, we need to show it in a 7 segment display just what my prof told to us...

10. ### techroomt Senior Member

May 19, 2004
198
1
i suppose then that you may be looking for devices that encode your (16) decimal switches to hexadecimal, and then another to latch (if needed) and drive the 7 segment.

11. ### daveglion Thread Starter Member

Jul 1, 2007
21
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yeah exactly..

12. ### daveglion Thread Starter Member

Jul 1, 2007
21
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i am planning to use 4072 IC (4 inputs) to replace the OR gates i used(7432 -only2 inputs
is that right? i am a newbie eh still needs the opinions of experts ^_^

13. ### thingmaker3 Retired Moderator

May 16, 2005
5,072
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If you are unwilling to simply use a PIC or EPROM or some such, then you must begin with a huge truth table and/or boolean expression. List the output states as a function of the input states. Look for patterns in the table or the expression. Adapt these to making your circuit.

Also: you can't do this with 16 input lines of binary coded decimal and only 8 o/p lines for hexadecimal. 9999dec = 270Fhex, so you'll need sixteen output lines instead of eight. These 16 lines would then control your display drivers, which in turn would light your displays.

This project is very complex for a beginner (unless using PIC or EPROM or such) and I am surprised an instructor would assign such a monster.

14. ### daveglion Thread Starter Member

Jul 1, 2007
21
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yup! my prof is such a monster!!!!

15. ### lightingman Senior Member

Apr 19, 2007
374
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Rite !!!!You sound desperate now.....Do this with an EPROM and 2 x CD4511's...I will work it out for you today, post a schematic tomorrow and if you wish to go that way, I will program you up an EPROM and stick it in the post for you...Daniel.

16. ### thingmaker3 Retired Moderator

May 16, 2005
5,072
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Daniel;
While your offer is a generous one, I worry that the young student will learn far less if they do not do their own work...

17. ### lightingman Senior Member

Apr 19, 2007
374
22
Hi,Yes I do totaly agree with you, and as I read it very quickly during a busy day, I missed that bit and did not realise that it was part of an assignment.....But and it is a big BUT, is it not the understanding and the constroction of a project that would teach the fundimentals of electronics, and the guy would still have to understand it's workingns fully to do the writing for it.....Whwt do you think ????...Thank you for pointing this out...Daniel.

18. ### daveglion Thread Starter Member

Jul 1, 2007
21
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Ei Sir sorry for the late reply...just got busy this days...
ei can you tell me or even explain me what is that EPROM and CD4511 plsss...,

19. ### daveglion Thread Starter Member

Jul 1, 2007
21
0
Anyway Sir tnx for the help....
I really appreciate it tnx...

May 16, 2005
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