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.

 

[marconi]

Earlier on, in your frequency counter post, we covered the unsuitability of diode resistor logic for AND or OR when used to detect a counter state and generate a very fast rise/fall and short duration reset pulse to RO1 and RO2 of the 7493. Because of the capacitance between anode and cathode of the diodes the circuit is too slow to produce one short clean reset pulse. Do you remember now? We had to use a semiconductor AND/NAND ic from the 74 or 40 series.

 

[_q12x_]

I managed to make this thing work in reality !

The (right) 4 logic probes here in the image are LEDs in reality, counting in binary.
This setup here is the same as the diodes one (but way more complicated)
The only problem is that I dont have any other 7430. This was the only one. And is most probably a slow TTL version, very old and made by romanians somewhere in 80's. The good news is that everything is working. Well, until the end of these 4 lines.
I just measured all the Buss lines and all the outputs and inputs and I pretty much get the same result as with the diode version.
VERY STRAAAAAAAAAAAAAAAAANGE!!!!!!!!!!!!
The only difference now, is that I can use those 4 leds counting in binary on the buss line.
But everything is UNDETECTABLE on those 4 bus lines !!! yet, it is working.
AGAIN> VERY STRAAAAAAAAAAAAAAAAANGE !!!!!!!!!!!!
Why I cant measure them? I still get a very WEAK signal, close to gnd.
Maybe I dont know how to measure this thing? How in the hell are you measure such thing?
AGAIN> VERY STRAAAAAAAAAAAAAAAAANGE !!!!!!!!!!!! WOW.

 

[_q12x_]

 

[marconi]

Good news. Thank you for the update. You have my suggestion for providing source and sink logic signals to your dtl logic gates to try out.

 

[_q12x_]

Indeed, and thank you that you watched my movie.
I just revert back to the diodes instead of the 8 input NAND and it is working....but for certain counts. Up to count to 8 everything works. But AFTER 8, is giving me errors. So the diodes not good in the logic side. I put back the 8 input NAND and tested every count. And I get this result:

Which is great news. Also the binary counting leds are doing their jobs fine, and also for the moment that single #1 module display also did it's job for everything so far.
I was thinking to replace this 4xAND diode gate with a 4input DTL NAND and a NOT also DTL.... But I will see.... What do you think? Should I ?
Next...probably I will have to make all the display #'s and see what 's*it' I will get from there.
This long tutankamon:

This is how is looking now in reality and is also working in the simulator as well with minor changes (R9) and some errors, but is working.
As you can see, no transistors on the BUS. Directly from the 7493 !!! Which Im not really a fan, but, it works.

 

[marconi]

I will check your posts but today and tomorrow I am visiting my elderly parents so I have less time to contribute(?) to your project.

I do not think you will be satisfied unless you test your Dtl logic gates first. You may need the source and sink circuit I sent you a diagram to drive 16 of them.

 

[_q12x_]

Im on the wave !
I managed to make the analogue version of a NAND Gate +a NOT Gate !
Tested from 2 to 16, all working as with the real chips.
Excellent !
Check the picture in the bottom of it.

 

[_q12x_]

 

[_q12x_]

also...

 

[_q12x_]