I understand the problem and what is to be done. No need for further clarifications !
So, I wish from now, good morning there and drink peacefully your English tea.
I actually throw this question to my other forum and my good american friend there completely understood me and give me straight the answer I was looking for. Read it for yourself as well since is very short and very to the point.
Led Matrix Display and switching RAM address problem - https://forum.allaboutcircuits.com/threads/led-matrix-display-and-switching-ram-address-problem.188934/
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The clarification:
This particular 2732 EPROM memory chip has 12 address pins, (A0-A11) this means 2^12 = 4096 addresses available
And 1 character is requiring 7 addreses to be displayed, by that 74LS93 counter.
for example letter A = 70 89 8A FB 8C 8D 8E
This means 4096/7 = 585 characters to completly full up the entire memory.
There are 26 letters in the alphabet and 10 numerals from 0 to 9.
In total 36 characters to be displayed.
36*7 = 252 addreses in total for the entire set.
where 2^8 = 256, this means 8 addr pins to be used.
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I am still looking like an idiot to the circuit and still have no clue how to proceed. Although I understand now that I have to somehow count each 7 lines for 1 character, I still need probably another counter to travel to the next 7 pack of addresses that contain the next character symbol in the memory. What should I add to 1-aquire the last address of the character and then 2-switch to the next pack of 7 addr ? Very complicated, especially for me that I am not that good with logic gates and analog IC's in general.
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One of my greatest ideas is to add a BIG counter. One that is counting to 256 (or 252) and then it is resetting back to 0 and starts again. I need it NOT to count by itself, but somehow stop from 7 to 7. And when I press a button, it will enable to get to the next 7 pack and stop there as well. In this time, it will get to 0 and count to 7. But if it is at addr 21 for example it will count to 28 and then reset to 21 again, count up to 28 and so on. So it will strobe the character at that particular sector. All these details, I didnt figure out, I only imagine them.