Pages: [1]   Go Down
Author Topic: DM74LS47N 7seg Decoder wiring  (Read 789 times)
0 Members and 1 Guest are viewing this topic.
berlin
Offline Offline
Full Member
***
Karma: 0
Posts: 154
fubbi.com
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset


Hello

Does someone know how to wire up a DM74LS47N? (http://www.alldatasheet.com/datasheet-pdf/pdf/51079/FAIRCHILD/DM74LS47N.html)
The outputs for the segments are obvious but I do not understand the inputs.

I need to hook up 4 of them.

Thank you!

Fubbi
Logged

Manchester (England England)
Offline Offline
Brattain Member
*****
Karma: 505
Posts: 31343
Solder is electric glue
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

The four inputs A0 to A3 define the number you will display.
~LT is the lamp test and should be wired high for normal operation.
The ripple blanking input depends on how you intend to wire them up. Are you going to multiplex the display or are the displays going to be on all the time?
But basically it allows leading zero suppression in multi digit displays, if that is what you want.
« Last Edit: November 22, 2011, 04:52:12 am by Grumpy_Mike » Logged

berlin
Offline Offline
Full Member
***
Karma: 0
Posts: 154
fubbi.com
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

How can I chain 4 of them? or do i need all those outputs for each chip?

thanks

fubbi
Logged

Manchester (England England)
Offline Offline
Brattain Member
*****
Karma: 505
Posts: 31343
Solder is electric glue
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

If the displays are going to be on all the time then yes you need separate outputs for the A0 to A3 inputs. Best done with two shift registers.
If you are going to multiplex them then you only need have one set of outputs for the A0 to A3 inputs as well as switching the anodes. In fact you only need one 74LS47.
Logged

Pages: [1]   Go Up
Jump to: