Hi I could really do with some help please.

I am a first year part time HNC student with very little experience in electronics and using Proteus, but i'm getting by so far.

My next assignment task is to apply a 555 timer to my working 16 character word circuit displayed on the 7 segment display. The timer needs to run the display at 1 second intervals. I am fairly confident with my resistor/capacitor values to achieve this, but I just can't get it right to display each of the 16 character letters. It's currently shows only the last letter!. What have I done wrong? What's missing? Any help would be much appreciated. thanks in advance.

 

Pins 2,6 of the 555 needs to be connected to R2,C1 junction.

 

Thanks for your reply but I have tried what you have suggested and it still doesn't seem to work. I can get the first and last characters to display now but not the rest

 

Hello,

Should there be a counter that goes through the 16 numbers?
Now A through D can only be 0 or 1 dependend on the 555 state and will all have the same value.

Bertus

 

of course thanks. perhaps a 4026 counter will work i will give it a try

 

It's currently shows only the last letter!.

Because that's how it is designed to work - it only has two states.

For it to display 16 states, you will need a counter that counts to 16 distinct states.

 

ah yes finally i've cracked it!!! i think
i've used a 4-input JK flip flop ( i think that's what it's called!!) lmao
It all looks good to me, all the characters are displaying.
wow that feels good!

many thanks