Logic Outputs Problem in 7493 IC

[_q12x_]

If you have 8 n channel power mosfet then but these can be connected common source to the 0V rail and a 1kR resistor inserted between each drain and the 5V rail.

Four of the mosfet have their gates driven by A, B ,C and D outputs of the 7493 and the other four by A*, B*, C* and D* derived from the four inverter gates you currently use. You can dispense with the 4 pnp transistors.

Connect the first 4 mosfet drains to the current logic busbars and the second 4 mosfets drains to a new set of 4 logic busbar. Now you can connect the 4 input dtl NAND with led as required to 4 of these 8 busbar to select the right 4 term logic operand term for the led. The eight busbars provide A, B, C, D, A*, B*, C* and D* the logic signals.

With this scheme you can avoid using dtl NOT gates.

I cant say I clearly understand ALL that you said here.
You are more clear in drawing cct than writing !!!
But I get the hint from your reading here, even if I dont completely understand it. To use mosfets as HIGH and LOW switching for the 4line bus. And most probably the other 4 you mention to be the 0V gate discharge. Its how I see it.
I will draw a quick cct of how ---I--- believe this should be. If its exactly as you explained here, then my sub-conscientious brain understood it, not the conscientious one. Haha.
Update soon.

 

[_q12x_]

I believe like this should work...

 

[marconi]

I cant say I clearly understand ALL that you said here.
You are more clear in drawing cct than writing !!!
But I get the hint from your reading here, even if I dont completely understand it. To use mosfets as HIGH and LOW switching for the 4line bus. And most probably the other 4 you mention to be the 0V gate discharge. Its how I see it.
I will draw a quick cct of how ---I--- believe this should be. If its exactly as you explained here, then my sub-conscientious brain understood it, not the conscientious one. Haha.
Update soon.

No that’s not what I meant. I will draw the idea soon.

 

[marconi]

If you were to use the 'standard' forms of DTL gates (my #16) I sent you examples of then my later idea was to generate A, B, C, D and A*, B*, C* and D* using the circuit attached. You then connect the 4 inputs to the appropriate busbar for the LED you want to light at a particular state of the 93's Q outputs.

I suspect - please confirm - that you are determined to (try to) make your version of DTL logic gates to work - therein lies most of the problem - they are not good designs and will have difficulty working alongside each other when connected to the logic busbars because they interact and this gets worse the more of them are connected to the busbars.

I would have 4 LEDs indicating the 93's Q outputs state to aid seeing what is happening.

Whether you have other problems/defects on your breadboards I have difficulty fathoming without them in front of me.

 

[marconi]

Ok, Try implementing the circuitry below for each Q output. It will produce for each Q output the option of sinking or sourcing current. Your DTL logic gates require for some inputs to be sourced and for the other to be sinked. I have illustrated this.

 

[_q12x_]

I modified your picture and interpret it my way.
Its an interesting idea... IF those mosfets will work as I planned in my #22.
Currently I have problems interfacing 1 single wire with 1 single led. Nothing worked so far (in reality). Only in the blody simulator.
Thats the problem....
Your idea will be 'plan B' if the 4 wires will not be enough and get errors on all those 16 # LEDs.

In the meantime I solved in the simulator the 555 delay problem... I have to try it in reality. Hope it works. Cross your balls for me.

 

[marconi]

Ok, Try implementing the circuitry below for each Q output. It will produce for each Q output the option of sinking or sourcing current. Your DTL logic gates require for some inputs to be sourced and for the other to be sinked. I have illustrated this.

This is for your dtl design.

 

[_q12x_]

So, check this out
I tested some more in reality and nothing worked.
What it did worked, my 555 super dupper cct, but directly on the pins of the 7493-not on the diodes and when the counting was over the pin I connected. So if it was counting to 8, my 555 was getting an impulse and its led on pin 3 was lit for the duration (delay) I make it to work.
So after some more failures, I decided to get rid of all those damn diodes because whatever I was doing I couldnt get any signal from them. This is it.
Instead, I BELIEVE, I did it the proper way now. I connected 4 leds directly to the 4Q's of the 7493 to gnd. I know it should be inverse, from + to Qpin, and I did it like that, but the leds were litting inversed. So I had to put them to gnd. Sourcing through the 7493 pin instead of sinking.
The good news is that now I have those 4 leds litting in binary - perfectly !
But I do not have that 4 input AND gate that I made from all those 4 diodes. You understand what I was doing now?
And thats not the only problem. I will need... probably 2 or 3 AND gates with 4 inputs, 1 here in the binary logic, and others in the display # LEDs. Aaaah.... When you dont have what you need.... hard stuff. I really thought I will pull it out with the diodes. Im so dissapointed....

 

[marconi]

There were two suggestions for you to try.

 

[_q12x_]

I happen to have only 1 one:
CDB430E Romania 1979 IPRS Baneasa equivalent to SN7430N 8-Input Positive NAND Gates
And that will pe good enough for the logic side.
But for the others.... thats why I got into great length, doing it with diodes.
I will built what I can, and leave what I can not make as a hole and put a label there "complicated".
But I will be able to make it work to a point. We'll see.
Im happy I find this 8 input NAND gate. I will have to transform it into a AND to do the proper job and every other pins will have to be linked to +5V (High).

I also have:
CDB410E x2 Romania 1980 IPRS Baneasa equivalent to SN7410N Triple 3-Input Positive NAND Gates
They may be handy.... Also I will have to transform them into AND gates as well.
We will see.
I also have
CD4081BE x20 AND gates
But until I will commit to the display module, I have to finish this logic side with 8 input NAND gate/transformed into an AND.