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  #11  
Old 12-21-2012, 09:30 AM
absf absf is offline
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Originally Posted by glenn_boy13 View Post
hey sir, by the way, the reason that I wanted to push myself to use just ONE MCU chip, is that, the chance of getting caught of using MCU in my project would be small. ) haha! Normally, in most of the arduino projects, they use shift registers. one 8 bit shift register for each 7 segment display. And If I use only one atmeg328p chip I will have to include two pcs of 74ls595 shift register ICs. And my professor wouldn't notice the big chip because of the two small ones.

thanks ! ^_^ But I realy want to know how to use the mux 74ls154. thank you so much! Im glad you are there
You can program the Arduino to do what the PIC is doing without using serial shift registers like 74HC595. To display 2 HEX digits with one 16F628a is also no big deal. Just has to add a simple mux and take care of the display timing.

Allen

Last edited by absf; 12-21-2012 at 11:50 AM.
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  #12  
Old 12-22-2012, 02:56 AM
glenn_boy13 glenn_boy13 is offline
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hi again sir allen. I already checked out your post #27. I just couldn't understand what you want me to know.

1. Yes sir, I know how to use just one MCU in arduino to display two hex digits in two 7 segment display WITH one 4-BIT Input. That will consume (8 + 8 + 4) 20 pins of the chip.
But I need another 4-bit input to make a total of 8 bits input.

You said that I just need to add a simple multiplexer, right? Could you please sir show me how to use the mux with your pic and your codes? I will just have to study them.

Anyway, about your mux post:
http://forum.allaboutcircuits.com/at...8&d=1355743793

The inputs are the ABCD, right? and the outputs are the Y0 to Y4. How is that related to displaying hex digits in 7 segment? hehe.
is it connected to this image (u2 and u3)?
http://forum.allaboutcircuits.com/at...7&d=1355743793
I don't know what is RN1 and RN2.
And I know that the 74ls47 is used only to display decimals. A-F are useless.

darn, sorry if I didn't get any of your suggestions.

Okay, to finalize... These are the ways I think I will do/use.

1. Because there are people who replied in my arduino post: http://arduino.cc/forum/index.php/topic,138482.0.html , I think, I will try their suggestions later. that will use shift registers. But, Im not yet sure if I will succeed in using that way.

2. The one you suggested sir allen, using one MCu chip with multiplexer.

3. Or the mux with basic gates.


thanks! I don't know if you will still help me. haha. I know the feeling of being questioned again and again.

Last edited by glenn_boy13; 12-22-2012 at 03:02 AM. Reason: sorry for large images
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  #13  
Old 12-22-2012, 04:53 AM
absf absf is offline
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Originally Posted by glenn_boy13
hi again allen. I already checked out your post #27. I just couldn't understand what you want me to know.
In post #27, you have to use Excel to construct 4 bit binary (input) and 7-bit a-g of 7 segment LED (outputs).

The example that I made is for binary to 2 BCD digits. From the table you can construct the circuit using 74154 and NAND gates which should give you the Binary to Hex output for 7-seg led.

Quote:
Originally Posted by glenn_boy13
2. The one you suggested allen, using one MCu chip with multiplexer.
I have drawn the circuit for 2 digits with a mux for the inputs. But my simulator has trouble with the VEE of the 4053 cmos mux and refuse to run. The software is still in progress and not yet tested. You might use it as a ref for your atmega328 or Arduino and see you can make it work.

Allen

p/s stop calling me sir pls just call me Allen will do.....
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  #14  
Old 12-22-2012, 05:11 AM
glenn_boy13 glenn_boy13 is offline
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Thanks again for your reply "Allen." hehe. Im only 19 years old, so I have to respect you. ^_^

1. Im very sorry because I have to ask you again about the mux with NAND Gates. ughhh, I didn't get it again. (
http://forum.allaboutcircuits.com/at...8&d=1355743793
In that picture, the outputs are y0 to y4. so we have a tota of 5 outputs, right? How am I suppose to connect them to the 7 LEDs of the 7 segment display? I should have 7 outputs.

2. What is the use of the PNP transistors? Are they really necessary? Of course I know what transistors can do. heheh. I just don;'t know why did you put such things.

3. Whats that RN1(rx8) thing?

4. uhmmm Allen, what software do you use? In my school, we use Multisim. It is similar to your software, but we, the computer engineering students don't use such software. hehe. we believe thats only for the electronics & communication engineering students. Lastly, I believe you already know the multisim software, right? ^__^. We always use such software for our Logic Circuits. IT can make and simulate different Logic Circuits. For instance, the one that you made in excel, I too can make such a table (4 bit inputs and 8 bit outputs for a-g) and then tell the program to make a logic circuit. Either using only NAND Gates or using only 2 bit input logic gates.


THANKSSSSS!!!!!! Wow, you are really a big help! ^__^ Don't worry. Im learning many things from you.

glenn
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  #15  
Old 12-22-2012, 05:38 AM
glenn_boy13 glenn_boy13 is offline
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http://i46.tinypic.com/xaw3p.jpg



I have watched one video that says VEE of the 4053 should be in ground hehe

Last edited by glenn_boy13; 12-22-2012 at 06:01 AM.
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  #16  
Old 12-22-2012, 09:01 AM
absf absf is offline
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Quote:
Originally Posted by glenn_boy13 View Post
1. Im very sorry because I have to ask you again about the mux with NAND Gates. ughhh, I didn't get it again.
http://forum.allaboutcircuits.com/at...8&d=1355743793
In that picture, the outputs are y0 to y4. so we have a tota of 5 outputs, right? How am I suppose to connect them to the 7 LEDs of the 7 segment display? I should have 7 outputs.
If you show me the truth table of your Bin to Hex. I can show you how to connect the 74154 to "a" segment of the LED. Fair?

Quote:
Originally Posted by glenn_boy13 View Post
2. What is the use of the PNP transistors? Are they really necessary? Of course I know what transistors can do. heheh. I just don;'t know why did you put such things.
The PNP is acting like a switch. When the base is at logic Low, the transistor conducts and the common Anode of the LED would get +5V. If you want to take a risk, you can connect the RA4 and RB0 directly to the Anode of the LED. But if there is a short on your LED, your mcu would get toasted.

Quote:
Originally Posted by glenn_boy13 View Post
3. Whats that RN1(rx8) thing?
8x 220ohm resistors in a 16-pin DIP package.

Quote:
Originally Posted by glenn_boy13 View Post
4. uhmmm Allen, what software do you use? In my school, we use Multisim. It is similar to your software, but we, the computer engineering students don't use such software. hehe. we believe thats only for the electronics & communication engineering students. Lastly, I believe you already know the multisim software, right? ^__^. We always use such software for our Logic Circuits. IT can make and simulate different Logic Circuits. For instance, the one that you made in excel, I too can make such a table (4 bit inputs and 8 bit outputs for a-g) and then tell the program to make a logic circuit. Either using only NAND Gates or using only 2 bit input logic gates.
I used Proteus Pro for schematic and simulation and ARES for making PCB.
I know multisim but never used it. It was quite good too. But I think you should learn LT Spice IV. Most of the experienced senior members use it. SO if you have any circuitry problem it would be easier to communicate with them.

Quote:
I have watched one video that says VEE of the 4053 should be in ground hehe
I tried but it doesnt work.

Allen
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  #17  
Old 12-22-2012, 12:15 PM
absf absf is offline
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Originally Posted by glenn_boy13 View Post
http://i46.tinypic.com/xaw3p.jpg



I have watched one video that says VEE of the 4053 should be in ground hehe
Hi your truth table is incomplete and the table is shadowed by another small window.\ so I cant see the details.

Could you pls post your picture here in PNG or PDF format so I can see it easily.....

Allen
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  #18  
Old 12-22-2012, 12:17 PM
glenn_boy13 glenn_boy13 is offline
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hi Allen, just got home! haha. I see, Rx8 is a set of resistors.

uhmm

ok sure, Ill show you the truth table. just show me how to connect some or one outputs to some or one led/segment of the 7 segment display using Multiplexer/Demux/Decoder. Oh by the way, haha, 154 is a demux/decoder, right? ^_^

here:
http://i48.tinypic.com/219bc.png

^_^ Thanks so much again!!!!!~

One thing I hate about my country: THERE ARE MANY UNAVAILABLE ICs HERE! not to mention the corrupt government officials. DM9368 is manufactured by FAIRCHILD, and the good news is, there is one branch of FAIRCHILD here, but located very far from the capital city. ughhhh!!!!!!!

glenn
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  #19  
Old 12-22-2012, 01:51 PM
absf absf is offline
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In your truth table there are 78 "1" and only 34 "0"....count them.

If I want to qualify with logic "1s", I would use AND gates. Instead I'll use NAND to qualify logic "0s".

Study my circuit carefully. Segments "a" to "c" are already done for you. So you just continue with the rest of the segments "d-g". Do it in your logicsim or multisim and see how it turns out. The 7-seg LED should be common Anode.

If you still dont understand how it works. Use a smaller model say 74139 (1 of 4 decoder) to display digits 0-3 using your table.

Allen
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File Type: png glenn_truthtable.png (47.1 KB, 13 views)
File Type: png bin2hex logic.PNG (33.8 KB, 16 views)

Last edited by absf; 12-22-2012 at 05:08 PM. Reason: add clarity
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  #20  
Old 12-24-2012, 02:54 AM
glenn_boy13 glenn_boy13 is offline
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hi sir allen. MERRY Christmas! thanks for all your help!
I ended up in using one ATmega328 MCU plus two 8-bit 74ls595 shift register.

If anyone here, or anyone from somewhere and luckily you have searched this thread, has the same problem, and you want to use arduino and shift register with inputs to display hex to 7 segment, just contact me

www.glennvon.com Im willing to help. hehehe



thanks sir allen!!!! :PP
Sir alen, I would like to seek some help from you about PIC in the near future. hehehe. do you mind? ^__^

glenn
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