AT28C16 EEPROM learning experiments

[_q12x_]

Thanks to mister @marconi , I received his chip AT28C16 gift from England !
I will start to make the 5x7 led matrix project that you did.
I will make it alone as much as I can (as usual). And I will ask you for clarifications on the way.

 

[_q12x_]

ofcourse, many parts of my instructions are to be used in general as well, not only dedicated to this particular recipe. To any food type. Feel free to play with it. Dont take it adliteram but 'with a gram of salt', as is the saying.

 

[_q12x_]

What is your 'clock' project about?
To simply make a clock? Thats it? I want to see if I understood you right.
So a clock that is showing hours, minutes, and seconds. Right? And for that to do it, it must "tick" or clock at very precise timing. From second to second for the second arrow if is mechanical or number if is electronic. Correct so far? Or your intention is something else than a real clock? Please be a tiny bit more specific that I to be sure what is the request exactly.

 

[_q12x_]

Watch this please:
Im presenting and explaining some stuff about clocks !

 

[marconi]

Digital Clock But Without a Microcontroller [Hardcore Electronics] - https://www.instructables.com/Digital-Clock-But-Without-a-Microcontroller-Hardco/

something like this but using what you have.

 

[_q12x_]

ok, but before the clock you told me about the gray code to use it with this EEPROM and led matrix. Remember? You give me a paper that was explaining in some sort of detail what the project was about. Very badly written by the way. Haha. But the idea was to use that gray code with a rotary switch and count the speed of a wheel or motor. The idea was good and I like it.
Why did you randomly switched to a clock now?

 

[marconi]

Something I thought you would like to do. I can guide you through a project to generate a 4 bit Gray code if you would prefer to do that.

 

[_q12x_]

I would like very much a circuit with it. No words just diagram. Can you find one?

 

[_q12x_]

Now I figure out why you stopped at letter 'P' in your circuit.
You didnt tell me this part. It was because you used your 7493 full count to 16.
I just cycled through my addresses and I counted 16 until back to A, which was the first. ANd Iwas curious what is on number 16 and it was 'P'.
Interesting.

 

[_q12x_]

And some big problem: - Tell me if you know about this problem and how to resolve it?
Thank you !

 

[marconi]

please draw me a circuit diagram for how the bottom left 7493 is connected.

do you have 10kR pull down resistors on each address line Of the eeprom?

Have you programmed the eeprom with letters B, C, D……..P - as you did for A?

 

[_q12x_]

Have you programmed the eeprom with letters B, C, D……..P - as you did for A?

not yet, I was about to do it but... I got this error in the memory I guess.
I only have an A in addr 00 another A in addr 01 and the rest are tests from before, with no meaning.

please draw me a circuit diagram for how the bottom left 7493 is connected.

 

[_q12x_]

do you have 10kR pull down resistors on each address line Of the eeprom?

teoretically yes, going through each led and its respective resistor.

 

[marconi]

teoretically yes, going through each led and its respective resistor.
View attachment 101919

No you do not because the LEDs are not conducting as there is no forward bias across them when the Q output is logic 0 ie at 0V.

Do you remember I mentioned the use of a buffer gate to drive an LED from an output? Drive the leds of the bottom left 7493 by the circuit I sent you earlier - #54 last paragraph and second attachment. Also connect each address line to 0V with a 10kR.

Have you linked the top rows of the 5V and 0 v rails at the mid point of the breadboard To the bottom rows of 5V and 0V rails?

 

[marconi]

These links on both sides of board.

 

[_q12x_]

yes everything is connected in line - no problem there
I dont have any buffer's - I just check my list of IC's and nothing.
I will have to put transistors instead, right?
I took out the leds and try it again, and guess what? is still the same, no change. So its not the leds not being driven by a buffer. I also have another 7493 that is counting to 7 and that is having the same 4 leds on its Q's and absolutly no problem ever from that one. So nothing should be from this one's as well, logically, right?