74ls193n 8 bit counter from 0-99

Discussion in 'Homework Help' started by travisram, May 4, 2011.

  1. travisram

    Thread Starter New Member

    Mar 23, 2011
    4
    0
    Hi i need help. My teacher gave us a project to do and didnt tell us how. WE have to make a now serving display that when you toggle the switch it counts up 1. We have to use 2 seven seg displays a 74ls47n binary to decimal drive. I know i need to cascade the 74ls193 to make a eight bit counter but i dont know how. i think after i get that set u i can figure out the rest. Any help would be greatly appreciated. And im using multisim 11. this is what i have so far http://i.imgur.com/U47Bu.png

    this is the full project
    Introduction
    In this design project, you will have the opportunity to draw together all of the concepts and skills that you have developed pertaining to the topic of synchronous counter design. You will design, simulate, and build a Now Serving Display. This is the type of display that you would commonly see at a deli counter.
    Equipment
    · Paper and pencil
    · Circuit Design Software (CDS)
    · Digital Logic Board (DLB)
    · Integrated Circuits (optional)
    o 74LS193
    o 74LS48
    o Common Cathode Seven-Segment Displays
    o Additional logic gates as needed
    · Jumper wires (optional)
    Procedure
    Design
    Design a digital circuit that displays the count from 00 to 99. This design has two control inputs and two output displays. The two inputs are Next and Reset. The Next signal comes from a push-button switch that, when pressed, advances the display by one. The Reset signal, which is also a push-button switch, will reset the display to a count of 00. If the display reaches 99 and the Next button is pressed, the count will roll over to 00.

    Design Specification:
    · The two output displays are common cathode seven-segment displays.
    · Current limiting resistors (150 W - 270 W) must be used.
    · Each display will use a 74LS48 BCD-To-Seven-Segment display driver.
    · The counting is controlled by two cascaded 74LS193 Synchronous 4-Bit Binary Counters.
    · Any additional logic may be used as needed to support the counter designs.
     
    Last edited: May 4, 2011
  2. travisram

    Thread Starter New Member

    Mar 23, 2011
    4
    0
    oh btw if i seem like a noob im take Digiatl Electronics in my sophmore year of high school so im new :)
     
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    The first thing you need is a data sheet. Use a search engine and "74ls193" to find one. Do the same for the 'LS48.

    Too bad you can't use 'LS192's that count in BCD (look that up, if you aren't familiar with it). To get a hex counter that goes from 0 - 15 to count 0 - 9, you have to use external logic to set the counter back to 0 instead of going up to 10 (Ah). That's a big hint.
     
  4. travisram

    Thread Starter New Member

    Mar 23, 2011
    4
    0
    I did they said that the BO and CO are used to cascade but my teacher said we dont need those. Also i di make a 0-9 that work i just need to figure out how to make a 8 bit counter using the 74ls193. this is my 1-9 and i works http://i.imgur.com/uWVA8.png
     
  5. Georacer

    Moderator

    Nov 25, 2009
    5,142
    1,266
    Think about the logic of the problem: You need the second counter to count up, when the first counter goes from 9 to 0.

    That means that the second counter must receive a positive pulse edge at that event.

    You can detect that event with logic gates. Wire a gate combination to detect the number 9. That circuit will output a '1' on the count of 9 and then drop back to '0', when the first counter resets. Can you imagine what you have to do next, since your counter is positively triggered?
     
  6. travisram

    Thread Starter New Member

    Mar 23, 2011
    4
    0
    that made alot of sense. the nand i had there gave a 1 everytime except when it went to from 9-0 so i just not that and put it to the next chip. i set the second chip to count from 0-9 also and then i set up the displays and it worked perfectly! Thanks a million!
     
  7. RD_80

    New Member

    May 8, 2011
    1
    0
    Hey, Sorry to bother you but is it possible that you could send me a picture of your final project. I didn't get to finish this at school and I don't have Multisim on my computer. It would be a great great great help since my Conclusion is due tomorrow! And do u possibly go to BTHS?
    Anyway, thankyou!
     
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