4516 Binary up/down counter

Vanwonky · Joined: Jul 24, 2013 Posts: 22 Location: Perth, Australia

Howdy Guys,

I tried breadboarding the 4516 (datasheet here) last night and got some very weird stuff happening. It may be nothing to do with the 4516 but maybe someone has experienced the same. The chip seemed to be reacting to the closeness of my hands / fingers to anything - the jumper wires, the IC itself, holding the breadboard, looking at it funny - you name it. I know stuff can go weird if inputs are not tied down so I did all and more with no difference!

Tried 3 different spots on the breadboard and another breadboard and batteries (9V) instead of my bench supply - nothing. Holding the positive pin wire really tightly made it work OK sort of but began to hurt after a while Sad

.

The other breadboarded modules still operated as per normal.

Any clues here?

Cheers
Dave

synaesthesia · Posted: Tue Aug 05, 2014 12:04 am Post subject:

Weird. Every time something like this happened to me it was a missing connection for one of the control inputs (enable, reset, ...) or even a missing power supply line. You checked that already. Are the left and right half of the power supply rows connected? Maybe one of the patch cables is broken.

Vanwonky · Joined: Jul 24, 2013 Posts: 22 Location: Perth, Australia

Hmm.. I will check those jumper wires tonight - never know. Yes left / right power was all good.

JingleJoe · Posted: Tue Aug 05, 2014 2:41 am Post subject:

remember that you have to connect every input on a cmos IC or the above mentioned glitches will happen.
A pull down or pull up resistor is required sometimes if you intend to use the input, but most of the time simply connecting the input directly to ground or +V will do.

Vanwonky · Joined: Jul 24, 2013 Posts: 22 Location: Perth, Australia

Gave it another go but reckon my 4516 has bombed out. I was at least getting it to count last night depending what my hands were touching but now - zippo - inputs grounded or not. Will get another ASAP and try again.

Vanwonky · Joined: Jul 24, 2013 Posts: 22 Location: Perth, Australia

Joy! OK - got it cranking. More fodder for my up and coming book "Lunetta for Absolute Twits"! Firstly I stripped my breadboard back to nothing - removing all other chips (I usually leave on after trying something out while space allows) and all wire pins connecting power to those chips and many more I still had in place. I am not saying this was the cure but maybe it didn't help the 'antenna' effect I was getting with my body parts.

Part two and more importantly, I connected every pin (except 7 - the carry out) to something. Now I had almost done that before except for the Enable pin 5 and the Reset 9. I was getting confused (as a newb) between my ones and zeros + and - so thought they could stay unconnected.

So a description like "DIRECTION 0=Down, 1=Up" means you have to connect to negative for down at least and not just leave it unconnected for "0". Is this right? Rolling Eyes

Happy to look like a dork if someone else doesn't have to waste hours with the same!

Cheers
Dave

PS: Oh oh! Synaesthesia said in his post - "Every time something like this happened to me it was a missing connection for one of the control inputs (enable, reset, ...)" Embarassed

rumblin_cynth_rampo

Vanwonky · Joined: Jul 24, 2013 Posts: 22 Location: Perth, Australia

Right - from now on everything gets tied down first and then I subtract from there! Wink

Vanwonky · Joined: Jul 24, 2013 Posts: 22 Location: Perth, Australia

And here is part of my problem. 4 hours trying to get it too work and 4 hours plus just playing with the new module instead of just getting it onto some veroboard! The 4516 is very cool. Lots of possibilities here.

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Vanwonky · Joined: Jul 24, 2013 Posts: 22 Location: Perth, Australia

Whoops - credit where due. JingleJoe also said connect everything!