Why you not just cutoff the space area, because there is no circuit over there.

 

well the 3 separate switches are for the 3 resets in the 4510 IC, by trial and error, i could do a reset. the fourth 4510 ic am not being able to connect it properly. And why does it start with 00:10? i had a similar problem before but i dont remember what change caused it stopped, i guess it was high voltage or lower frequency.

Remove U14 (AND2 chip connected to U9). It does nothing but mess this up. This digit should go 0-9, just like digit 1.

 

the fourth 4510 ic am not being able to connect it properly.

You changed the connections to the second digit and now it doesn't work correctly. Why can't you enable reset on the 4th counter?

 

Also, your reset for digit 2 (MM:SS) should look like this.

A reminder. This is the Homework Help forum, not Homework done for you...


Mods edit:
The circuit was deleted, thank you.

 

A reminder. This is the Homework Help forum, not Homework done for you...


Mods edit:
The circuit was deleted, thank you.

Yes they are helping only Sir. For me this is great help, because not being electronic students i am not used to these and without these small or big help, i am not going to move ahead at all. AAC is a place where electronic experts help those who dont know as it seems. And i am of those weak in electronic.

 

Yes they are helping only Sir. For me this is great help, because not being electronic students i am not used to these and without these small or big help, i am not going to move ahead at all. AAC is a place where electronic experts help those who dont know as it seems. And i am of those weak in electronic.

Homework is a special case. We are expected to guide you to a solution so you can learn; not do your homework for you.

 

Especially thank you a lot GopherT ive been able to move forward with your help. Some changes were required otherwise it would not work fine. There is a problem of increment when i am resetting. The last one increments each time i close the switches. I guess this is because the OR is ORing with the power, something like this and the AND from 3rd 4510 ic! am i correct? i have tried diodes to negate the logical states or switches to open the circuit of the last OR, but tht doesnt help. am i quite on the track?

I would love to thank all the others who are also helping me a lot

 

Post a schematic for what you have wired. You should wire so all of the counters are reset at the same time. Make sure that the changes you're making don't affect the parts that were working.

 

Yes Sir ive made my maximum. So here it is. i tried it on a copy of original work

 

i posted, but it was not appearing on the webpage. So i am uploading all 3 extensns of the snippet

 

Why are you using an OR gate (U19) for the reset of the first stage? What were you taught to do with unused inputs? How is the 4th counter (U12) supposed to be reset?

Have you verified that the counters are counting correctly? I still see problems.

 

There is a problem of increment when i am resetting. The last one increments each time i close the switches. I guess this is because the OR is ORing with the power, something like this and the AND from 3rd 4510 ic! am i correct?

Examine the reset and clock logic for the last 3 counters. It should be obvious why some of the counters are incrementing when you're trying to reset.

Why did you change CI for the last 3 counters? It was wired correctly before.

 

i did it for the reset! it's all good!! From my snippet, without affecting the reset part, how do i proceed for pause? i know 4510 is a latch as well, so it can hold data when on pause,i.e., i am sure in a way there is no need to add other ICs. for 4511 ic ive read that we can do the pause function by manipulating the ENABLE. ive read the datasheet of 4543 display driver, but there is no mention to keep the timer on pause.

 

Read about the Enable/Preset input here.

How can you pause the counting?

• Use a chip input.
• Control the clock.
• Discover another method.

 

You have two OR gates with floating inputs and you've broken the counter.

 

Hi ScottWang
I really sorry. I get carried away by the lack of time that the OP has to present his design.
Surely I will not do again.

As others have noted (and this is a general comment not directed at you specifically, MrCarlos), the lack of time is almost certainly due to poor planning on the OP's part. That is part of what they are supposed to be learning and if someone comes to the rescue then they are robbed of the opportunity to learn that lesson in an environment where all that is at stake is the grade on a project.

Our attitude here should be that how much or how little time a poster has to work on their project is immaterial -- we provide guidance in response to the efforts put forth by the poster and the rate at which that progresses is governed by the efforts of the poster. The fact that they are coming here for help on things that they are supposed to be able to do on their own (which is fine) means that they should be being proactive and coming here well before any deadlines for the work in question.

 

Could u please help me out??? evrything was going fine..upon test i found out that it doesnot stop at 59:59 but goes beyond. COuld u please help? i have 1hour left before submitting it. i am trying and not able to think of a solution. Only last connectn has to change in last 4510

 

evrything was going fine..upon test i found out that it doesnot stop at 59:59 but goes beyond.

Look at the reset logic for the last counter. You disconnected it when you were trying to implement reset.

Your simulation may be showing you correct counting, but you should have a clock stuck at 1 for the 3rd counter. You have wire OR'ed two outputs.

Your reset logic is still wrong. It will increment the 3rd and 4th counters.

The 3rd counter should be counting 0-8 and resetting on 9.

The 3rd and 4th counters shouldn't be counting because CI isn't LOW. The 2nd counter should have the same problems.

The simulator isn't very good if it can't show you these problems.

 

Hello,

Why are you not able to produce smaller images.
Here I reduced your image of 1.8 MB to about 80 kB:



Bertus