# help in connecting mod 16 counter to LED

Discussion in 'Homework Help' started by sunshine90, Jan 2, 2008.

1. ### sunshine90 Thread Starter New Member

Jan 2, 2008
2
0
hi. i need help in connecting a mod 16 counter to the LED digital display. the diagram is in the attachment..

i've already connected QA to CLK B and the 2 master resets to ground.. the others i m so stuck! can u show it to me how to draw? i've got a test soon

thanks =)

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2. ### beenthere Retired Moderator

Apr 20, 2004
15,808
295
For either display driver - QA to input A, QB to input B, etc.

You seem to have some problems, though. If your counter is binary, the 7 segment driver may or may not be capable of handling hexidecimal data. If so, you will need to use BCD counters. You may also have to do an extra counter to make a source for the second display.

It would be a good idea to pick a logic family to use and label the ic's with the device numbers.

3. ### sunshine90 Thread Starter New Member

Jan 2, 2008
2
0
isn't mod 16 causes the 7 segment display to display from 0 to 15? tat's why i draw 2 displays because of the 2 digits. is it correct?

4. ### Papabravo Expert

Feb 24, 2006
12,212
2,697
I don't think so. A modulo 16 counter has sixteen states representing the numbers in the range [0..15]. Each of those numbers can be represented by four binary digits. To make a two digit decimal display you need to decode the four binary bits and write a series of boolean equations to activate the correct segments for a two digit display. One way to do this is with a truth table like the following

Code ( (Unknown Language)):
1.
2. Inputs        left d    right digit
3. D  C  B  A  | c  b  | g  f  e  d  c  b  a
4. 0  0  0  0     .....
5. .
6. .
7. 1  1  1  1     ......
8.
The letters DCBA represent the states of the binary counter. left d letters c and b represent the two segments on the right hand side of a 7-segment digit which will either be blank(off) or displaying a 1. right digit letters gfedcba will represent the segments of the right most digit.

You could easily do this with a ROM, a PAL, or a microprocessor.