I need some help please.

Hey guys.

I'm a new arduino user, and I'm wondering if it's possible to connect two 74HC4511's to drive two 7 segment displays. Or can I only drive them seperately?

Yes you can connect two 74HC4511 together, that is common up all the input pins to the arduino's output pins. The only thing you will have to be separate is the latch pin so you can control what display you write to.

Thanks bro! With the 74HC4511's connected will I be able to send out a binary number like 10100, and the segments will write out 20? - Sorry for all these questions, as I said I'm totally new to this.

  • Saur

First of all a few hints on how to be more successful at getting help.

(1) Virtually everyone who posts a question on the forum needs help with something so a subject of ‘I need some help please’ doesn’t provide any new information. A better subject in your case might be something like ‘74HC4511 with multiple 7-segment displays’.

(2) A link to the datasheet for the 74HC4511 would be good for two reasons. It would relieve the people who want to help you from the task of first searching for a datasheet and it would prove to them that you had already done some preliminary research

(3) This might fit better in the ‘LEDs and Multiplexing’ forum. It’s possible that some local LED expert wouldn’t even read an LCD biased forum.

Now - on to your question. I’m not sure what you are asking when you ask “Or can I only drive them seperately?” I think you want to drive the BCD inputs of two 74HC4511 chips from the same Arduino I/O pins. I believe you can do this by dealing with the two LE pins individually. Put the data for one display on the BCD data pins and enable the latch for it’s decoder/driver. Then put the data for the other display on the BCD data pins and enable it’s latch. Just make sure you have only one latch enabled at a time.

Don

Edit: Mike types faster than I do.

Thanks bro! With the 74HC4511's connected will I be able to send out a binary number like 10100, and the segments will write out 20? - Sorry for all these questions, as I said I'm totally new to this.

No. The 74HC4511 requires BCD (Binary Coded Decimal) data. You will have to deal with each digit separately. 10100 in binary is 0010 0000 in BCD. You send the 0010 to the left display and the 0000 to the right display.

Don

Oh, you're right! I will be more specific and detailed next time.

To be more specific on my project, I am trying to make a temperature sensor using an LM35 sensor, and I want to make the temperature show on the two 7-segments, using two 74HC4511's.

For future readers, the datasheet for the 74HC4511 is here: http://www.sparkfun.com/datasheets/IC/74HC4511.pdf

  • Saur.

EDIT:

Oh, that's what I thought, thanks for the help!