Hi all
Have looking for a solution to the following problem without finding anything.
Have attempted to design a preprogrammed DOWN counter with 3 digits, seconds, 10 seconds and minutes.
Uses 3 x CD4510 and have problems with 10 second decade.
Problem 1, how to get 10 and one second to figure 59-00.
Problem 2, the ability to preset the counter at a selectable time.
Please see my link:

Regards
Lennart

 

Is this homework?

Search the forum... There have been other posts with a similar problem. Like this one.

 

Hi all
Have looking for a solution to the following problem without finding anything.
Have attempted to design a preprogrammed DOWN counter with 3 digits, seconds, 10 seconds and minutes.
Uses 3 x CD4510 and have problems with 10 second decade.
Problem 1, how to get 10 and one second to figure 59-00.
Problem 2, the ability to preset the counter at a selectable time.
Please see my link:

Regards
Lennart

You need the 1-second pulse to enter to 1's digit decade counter. Every time it rolls over, it sends a pulse to the 10's second decade counter.

Look at the multiple posts with google searches - the key is to see how the tens-second decade counter is configured to reset to zero instead of going to 6 while sending a pulse to the minute counter to increment.

Then look for the word Latch, changing that pin will allow you to capture the starting value in the chip with the A, B, C and D pins.

 

Thanks djsfantasi and GopherT.

I can't find any solution in the forum.
I know how I can get CD4510 to count up from 0-5.
My problem is how I get 10 seconds to count down 5-0 while I shall have the opportunity to preset it to any value?

Regards
Lennart

 

Thanks djsfantasi and GopherT.
I can't find any solution in the forum.

The link I provided was not useful? If you didn't recognize it, click on the blue underlined letters in my other post, or click on the words " Like this one."

 

Mr. djsfantas

I assume you mean "elec mech" from Nov. 2 2011.
But I do not understand how to combine the preset 5 for 5-0 in the clock and the preset of any number to the buzzer.
Please see my attached file, where I tried to solve the problem.

Lennart

 

Clarification of my problem

Best regards
Lennart

 

I don't see any attachments or clarification?

 

Clarification of my problem.
Please open Word dok3
Sorry #7 was wrong.
Best regards
Lennart

 

Hi Lennart Westling

Have you any progress in your design?
Let me give you some tips.
As I understand you require a programmable Stopwatch with 3 digits. 2 for the seconds and 1 for the minutes. must also count down.
So we can name it as: Programmable, Count Down, Chronometer 00-10 Minutes
Many more devices that show in the attached image in your post #9 are required.

I can identify four sections:
- The countdown stopwatch itself.
- One circuitry to select between count and set the time to start.
- Something named Clock Control.
- A control panel with something you name "tumb wheels" three of them. buttons and switches to setup the operation mode.

Now, Your Questions:
Problem 1, how to get 10 and one second to figure 59-00.
Problem 2, the ability to preset the counter at a selectable time.

For the 1:
You must take in consideration the couple of IC's counters. The one for units of seconds and the other for tens of seconds,
As soon as this two counters reach 00 You must SET Them to 59. And the minutes counter should count -1.
How to do this?. . . Easy, program the 8, 4, 2, 1 inputs on your design accordingly:
Tens of seconds: 0101, Units of seconds: 1001. Then apply a positive going pulse to the input named LD of your 4510 IC's.
This way the data on the inputs 8, 4, 2, 1 will appear on the outputs Q8, Q4, Q2 and Q1.
BUT. . . you need to program some time where to start counting. Here is where you need a Data Selector circuitry because we need to use, also, the inputs 8, 4, 2, 1, on your 4511 IC's. And The LD Input.
Select between:
Program 59 when the chronometer reach 00. OR
Program the time where to start counting.
I think these last paragraphs answer your question in Problem 2.

By the way, what is the software name you use to simulate your designs?

I hope this talk will serve you to continue your project.

 

MrCarlos

Thanks for your comments.

You Wright:
BUT. . . you need to program some time where to start counting. Here is where you need a Data Selector circuitry because we need to use, also, the inputs 8, 4, 2, 1, on your 4511 IC's. And The LD Input.

That's exactly what I need.
That is my problems.
Would be grateful for an example of such a link.

Regards
Lennart

 

I forget.
I use Yenka for simulations.

Lennart

 

Hello Lennart Westling

We are going to have some problems because I have not the Yanka SoftWare.
I mean, I don't know if this SoftWare has some IC's Like:
74LS541 Octal Buffer/Line Driver With 3-State Outputs. 8 BIT’s
74LS244 Octal Buffer/Line Driver With 3-State Outputs. 4 BIT’s
The important here are its characteristics of 3-State Outputs in order to connect someone’s in parallel.
Like, You can see, in the attached File: Data Selector.PDF or In The Data Selector.PNG, Attached too.
Also are attached datasheets for this particular IC's in order you can study with the intention to discover its operation.

Let me tell you something about this 3-State.
Before now the outputs of the logic circuits had only two states: 1 and 0
But now there is a 3-State: OPEN circuit.
So now there are 3 states:
1
0
3-State.
This probably You already knew.

So well. let me tell You some words about our data selector circuit.
Try to keep an eye on the circuit contained in document Data Selector.PDF.
You can find an connector named Select, Ok?
By means of its logic state We can SELECT:
U2 U2:B Data Inputs = 0.
U1 U2:A Data Inputs = 1.
Read '=' Sign as -If equals to-

Note the very small colored squares.
Red is logic level 1.
Blue is logic level 0.
Gray is logic level Undefined. because is nothing connected to.

Actually the only Thumb Wheel on the scheme has on its face a 3. and its output connectors are named:
UM-P1, Units of Minutes, BIT 1.
UM-P2, Units of Minutes, BIT 2.
UM-P4, Units of Minutes, BIT 4.
UM-P8, Units of Minutes, BIT 8.
Are you following Me?
- See the number 3 (1100) on the outputs of IC U2:B. . . Why?.
- What binary number is preprogrammed on U1 BIT's: D1, D2, D3, D4 ?
- Why U2:A has on its outputs the binary number 3 (0011) if on its inputs has the binary number 9 (1001) ?

 

MrCarlos

Thank you for your interest.
Is just about to put myself in your description.
My simulator is Yenka.
My IC circuits is C-MOS CD4510.
But it should be possible to use CD40373 instead of SN74LS541.

Regards
Lennart

 

Hello Lennart Westling

Yes, You could use CD40373 instead of SN74LS541.
But make a good search. I saw, some were in the WEB, that these devices (CD40373) are potentially obsolete.
Take care of this.
If You find This IC in your country, electronic stores, Ok, go ahead.