Interfacing 8-bit ADC to 7-segment display

[cybertron]

Hi.

This is what i been try to do. But? didn't have or known the right parts to use.

I seen this circuit and want to know.Both circuit enclosed.

1.How do I use (4) 7-segment displays with this circuit setup.
Then I need the displays to function from left to right the right display will be the last digit to display its output number.
So the functioning needs to work like this.decoder displays first number whether 0-9 that number stays on then the decoder display second number on second display that number stays on then the third number and the same for the last number whether 0-9 for each display. they will all stay on until a new set of number are sent to the decoder and decodes those numbers.Or a reset momentary switch reset all displays to zero.Can you send me a revised schematic for this setup for my needs to the MULTIPLEXED BCD 7-SEGMENTS DRIVER CIRCUIT. PLEASE HELP.


2.Then interface the ADC 0808 output too the CD4553 input.How do I do this.
Maybe I still need to add another chip to interface the ADC TO the 4553 in the second part of the circuit.

 

[erikl]

2.Then interface the ADC 0808 output too the CD4553 input.How do I do this.
Maybe I still need to add another chip to interface the ADC TO the 4553 in the second part of the circuit.

Right. You need one more counter: an 8bit programmable down counter, e.g. CD/74HC40103, which you load from the ADC 8bit output, and which generates the latch enable signal for the CD4553. For both chips you could use the same clock signal, perhaps the same or a down-divided one from the ADC clock. Plus probably a few logic gates to handle the control signals.

Or you use an ADC which can execute all this by software.

 

[simonbramble]

You might also want to look at the MAX7221. This takes much of the headache out of interfacing to 7 segment displays, handles the dimming etc

 

[FvM]

You describing a system comprised of a numeric keyboard, a 4 digit display and some logic that processes keyboard entry.

The schematic in your post (a 3-digit decimal counter) is mostly unrelated to this problem, except for the fact that it has numeric display, too.

Secondly you plan to interface a 8-bit adc with binary output to the decimal counter. To achieve what? To display the ADC measurements as decimal numbers, you need a binary to decimal converter, not a counter. And how is the ADC related to the keyboard unit presented in the first part of the question?

These days, most people would use a microprocessor to convert ADC measurements to decimal display. It can be basically done with "hardwired" digital logic, but involves a larger number of logic ICs.

 

[cybertron]

FvM

The schematic in your post (a 3-digit decimal counter) is mostly unrelated to this problem, except for the fact that it has numeric display, too.

In part 1 of my post I ask how do i add another display to the already 3-digit decimal counter. So I could Have 4 displays instead of 3 displays. And what added IC will I need to use too do this.

That's the first thing I need to start with,then I could go to part 2 of the circuit.

- - - Updated - - -

You might also want to look at the MAX7221. This takes much of the headache out of interfacing to 7 segment displays, handles the dimming etc

Thanks But? I want to use ICs that I will not need to use a Micro-controller.
This IC needs a controller to work.

 

[FvM]

4553 is a 3-digit (count 0...999) decimal counter, it can't be extended to 4-digit. To make a 4-digit counter, an additional 1-digit decimal counter with decoder could be connected to the 4553 overflow output. Or use a different counter circuit supporting 4-digits (count 0..9999).

However, the problem presented in post #1 isn't related to counting. So it's completely unclear how you "could go to part 2 of the circuit" after making the 4-digit counter work.

 

[cybertron]

4553 is a 3-digit (count 0...999) decimal counter, it can't be extended to 4-digit. To make a 4-digit counter, an additional 1-digit decimal counter with decoder could be connected to the 4553 overflow output. Or use a different counter circuit supporting 4-digits (count 0..9999).

However, the problem presented in post #1 isn't related to counting. So it's completely unclear how you "could go to part 2 of the circuit" after making the 4-digit counter work.

In post #1 I wanted to use the 4553 3-digit counter and add one to make it a 4-digit counter.But as stated it cannot be extended to a 4-digit counter.So I search again
for a 4-digit counter and found the 74C926. Would this chip take the place for a 4-digit
counter.And what 7-segment displays should be used common anode or common cathode.And will i be able to still use the 74LS48 BCD DECODER to the 4-digit counter.

Also how do i get the counter to work as explained in post one part 1. And no micro controllers.

 

[FvM]

The display connection and suggested type is given in the datasheet:


The IC counts clock pulses and can't be controlled by digitwise key input, same thing as previously discussed. You're still on a wrong track, I fear.

 

[cybertron]

The display connection and suggested type is given in the datasheet:


The IC counts clock pulses and can't be controlled by digitwise key input, same thing as previously discussed. You're still on a wrong track, I fear.

I didn't see that part in the datasheet when I look at it.Should of look at the entire document.It states common cathode. But I also did another search on google images and I seen the 74C926 connected to common anode displays. Can this IC use either display. OK? I understand that this IC is not controlled by digit wise key input.Or from a keypad.
But it can read a binary code. right? like 0000= 0 or 1001=9.etc. Or can it. I'm not going to be using a keypad foresay. Do I still need to use the 74c922 or Both, in some way.
And I'm not using a keypad with the 74c922 just trying to get or pick up a signal
that will have a binary number in the ANALOG signal.That's where the ADC COMES IN TO THE CIRCUIT. If this makes any since to you.

 

[FvM]

trying to get or pick up a signal that will have a binary number in the ANALOG signal.

Means what? Making DVM (digital voltmeter)?

 

[cybertron]

Means what? Making DVM (digital voltmeter)?

No? Not exactly.

I want to pick up a binary number or numbers in a source signal
whether its an audio recording or from a keypad or from
oscilloscope.And decode that number on a LED 7-seg display.

I've enclosed a block diagram and signal example of what I'm trying to explain and what I'm trying to do. An image of a signal example that is a digit that could be an input number from 0-9. I do not know if this signal example is analog.digital or analog with a digital signature.

Can you tell me what kind of signal this is in the (Signal image example) that I've enclosed.
This is why you might not be able to understand what i want to do.This is the Best way to explain what i need to do.As apposed to post #1 and post #9.

 

[FvM]

If you don't know how the sound sample is coding a number 0-9, how should I?

Sounds like we are back to your previous thread https://www.edaboard.com/threads/328652/

One possible coding scheme is of course DTMF. But the block diagram makes no sense for it. Instead you could use an DTMF decoder chip (see above linked thread) and design a logic that transfers incoming DTMF codes digitwise to a registers and displays in on the 7-segment displays. It won't involve an ADC but a control circuit that has to decide about start and next digit of a number sequence based on predefined timing criteria.

 

[cybertron]

If you don't know how the sound sample is coding a number 0-9, how should I?

Sounds like we are back to your previous thread https://www.edaboard.com/threads/328652/

One possible coding scheme is of course DTMF. But the block diagram makes no sense for it. Instead you could use an DTMF decoder chip (see above linked thread) and design a logic that transfers incoming DTMF codes digitwise to a registers and displays in on the 7-segment displays. It won't involve an ADC but a control circuit that has to decide about start and next digit of a number sequence based on predefined timing criteria.

Sorry about that blocking diagram it was the best way I was able to
explain it.

Its not DTMF. So it must be 1 0r 0 binary code but digitized as an analog looking
signal.

But if it is DTMF. Assuming that it is. Then how do THIS.

Instead you could use an DTMF decoder chip (see above linked thread) and design a logic that transfers incoming DTMF codes digitwise to a registers and displays in on the 7-segment displays. It won't involve an ADC but a control circuit that has to decide about start and next digit of a number sequence based on predefined timing criteria.

I need more help with the transfer of the DTMF TO registers and how many registers would I NEED. Plus?
The control circuit that has to decide the start and next digit sequence based on the predefined timing criteria. some type of circuit would help me out.

 

[FvM]

Its not DTMF. So it must be 1 0r 0 binary code but digitized as an analog looking
signal.

But if it is DTMF. Assuming that it is. Then how do THIS.

I really can't imagine how you will design anything without even knowing the envolved coding method.

If it's DTMF, you can at least refer to an existing decoder chip.

I would start the control circuit design with a state diagram that describe the different states during digit entry. Starting with an idle state waiting for the first digit to be entered.

 

[cybertron]

I would start the control circuit design with a state diagram that describe the different states during digit entry. Starting with an idle state waiting for the first digit to be entered.

I don't understand this at all what do you mean state diagram.Or even know where to start.

And how many coding methods can there be if its either DTMF OR binary ones and zeros.Digital 0-9.
The DTMF decoder chip or circuit I can do.But the rest you mention I would need a circuit diagram to work with.

I have given you information on what I need the best i could explain it.You have explained or gave me little to work with. I'm not an engineer.Where I can just come up with the DESIGN.I do this as a hobby.This is why I'm here.For Help with the design. If I could design what I need on this project
I wouldn't need to be here or ask for help.

Can someone else Help me. who understands what I need and who's an Engineer in electronics.And is willing to provide circuit and more info to my project.

 

[FvM]

A state diagram is a method to describe the intended behaviour of your control circuit. https://en.wikipedia.org/wiki/State_diagram

In my view it's a good point to start together with a definition of input and output signals. If the control circuit function is quite obvious, you could skip the description and start to sketch a circuit.

The input signals can be the detect pulse (e.g. 8870 StD signal) and the 4 BCD outputs of a DTMF decoder. You specify that after a quite interval of at least 10 sec the control logic should be reset and starts with the first digit. The display can be either cleared or maintained when the 10 sec timer elapses.

The first detect pulse transfers the number to a register for the first digit and advances the logic state to awaiting second digit. And so on.

You furtherly have to decide how the display should look during number entry. A new digit could be either displayed in rightmost (LSD) position and the previously entered number shifted left. Or each digit entered in a fixed position left to right.