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Forum: FPGA, VHDL & Verilog Calculator from keyboard display 7seg


von Ali R. (Company: ABC Assembly) (alirahiminezhad)


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The input numbers of this calculator have a maximum of 5 digits, and the 
recognition of the input number depends on how the keys are pressed by 
the user.
If user first press 5 and "+" means user wants to add the one-digit 
number 5 to the next number she wants to enter, but if user press 5,then 
press 9, then press 1, then press "+" means user wants to add 
three-digit number 591 to the next number she wants to enter.

von Lothar M. (lkmiller) (Moderator)


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Fine that far.

But whats the actual problem here? On what platform? With which 
toolchain? In which language?

von Ali R. (Company: ABC Assembly) (alirahiminezhad)


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Lothar M. wrote:
> Fine that far.
>
> But whats the actual problem here? On what platform? With which
> toolchain? In which language?

It takes a number from the input until an operator arrives and I do not 
know how to tell this to the machine. exp) first press 5 second press 7 
third press 4 fourth press "+" fiveth press 9 ==> 574 + 9

I want to implement on your Spartan7 discovery board with VHDL

von Lothar M. (lkmiller) (Moderator)


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Ali R. wrote:
> It takes a number from the input
Which "input"? What is your input device? How do you determine a 
"press"? May there be a "bouncing", so that you must debeounce the input 
singals? How do you come from a "press" to a input value?

> and I do not know how to tell this to the machine
How would you do it on a sheet of paper? What steps are necessary? How 
do you com from "first press 5 second press 7 third press 4" to a number 
"574"? What can be the maximum number? What if someone presses more 
keys?

> fourth press "+"
Are there other operators possible here?

Try to answer those qouestions. You will have to anyway, if not now, 
then later on...

von Ali R. (Company: ABC Assembly) (alirahiminezhad)


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Lothar M. wrote:
> Ali R. wrote:
>> It takes a number from the input
> Which "input"? What is your input device? How do you determine a
> "press"? May there be a "bouncing", so that you must debeounce the input
> singals? How do you come from a "press" to a input value?
>
>> and I do not know how to tell this to the machine
> How would you do it on a sheet of paper? What steps are necessary? How
> do you com from "first press 5 second press 7 third press 4" to a number
> "574"? What can be the maximum number? What if someone presses more
> keys?
>
>> fourth press "+"
> Are there other operators possible here?
>
> Try to answer those qouestions. You will have to anyway, if not now,
> then later on...


1.Number between 0000 to 1111 is my input and independent these number 
calculation make decision
0000 to 1001 == number
1010== "+"
1011=="-"
1100=="*"
1101=="/"
1110=="="
1111== nothing
And i press input on a keyboard.
2. Inputs in my system have a maximum 5 digit and I said each digit is 4 
bit
3.I upload image with detail
4. And this operation display on 6 seven segment and 1 7seg for sign 
result
Thanks

: Edited by User
von Lothar M. (lkmiller) (Moderator)


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Ali R. wrote:
> 1.Number between 0000 to 1111 is my input
> And i press input on a keyboard.
Thats a 4 bit vector. And in real life the bits of a vector never ever 
change at the precise same picosecond, so how do you validate the 
vector? Is there an additional signal that tells you: "now, this is the 
correct bit pattern"? Or do you have to say: "its a valid input when the 
input value doesn't change for 100ms".

> 0000 to 1001 == number
That are BCD numbers (binary encoded decimals).

> 1010=="+"
> 1011=="-"
> 1100=="*"
> 1101=="/"
> 1110=="="
> 1111== nothing
> 2. Inputs in my system have a maximum 5 digit
So the numbers can range from 0 to 99999 and 99999*99999 is 999980001 
and therfore to much for a integer, so you must do the calculations in a 
vector. But thats also a problem for your calculator display, because 
999980001 are 9 digits and thats to much for a 6 digit display...

> 3.I upload image with detail
What should be shown the display whan you enter

3434 - 1212 =

Or

1234 + 5678 - 1000 =

Or

1111 - 2222 = + 3333 =

You must answer this first, because you canot display + - * and / on a 
7seg display.

The whole task is fairly demanding and tricky in the details. So fist 
you must get some structure in the "big tasks" you have to solve: input 
data, entering values, calculate result, display thingies. These "big 
tasks" you have to subdivide in "small steps" you can handle in state 
machines.

BTW: what background on VHDL do you have?

von Ali R. (Company: ABC Assembly) (alirahiminezhad)


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Lothar M. wrote:
> Ali R. wrote:
>> 1.Number between 0000 to 1111 is my input
>> And i press input on a keyboard.
> Thats a 4 bit vector. And in real life the bits of a vector never ever
> change at the precise same picosecond, so how do you validate the
> vector? Is there an additional signal that tells you: "now, this is the
> correct bit pattern"? Or do you have to say: "its a valid input when the
> input value doesn't change for 100ms".
>
>> 0000 to 1001 == number
> That are BCD numbers (binary encoded decimals).
>
>> 1010=="+"
>> 1011=="-"
>> 1100=="*"
>> 1101=="/"
>> 1110=="="
>> 1111== nothing
>> 2. Inputs in my system have a maximum 5 digit
> So the numbers can range from 0 to 99999 and 99999*99999 is 999980001
> and therfore to much for a integer, so you must do the calculations in a
> vector. But thats also a problem for your calculator display, because
> 999980001 are 9 digits and thats to much for a 6 digit display...
>
>> 3.I upload image with detail
> What should be shown the display whan you enter
>
> 3434 - 1212 =
>
> Or
>
> 1234 + 5678 - 1000 =
>
> Or
>
> 1111 - 2222 = + 3333 =
>
> You must answer this first, because you canot display + - * and / on a
> 7seg display.
>
> The whole task is fairly demanding and tricky in the details. So fist
> you must get some structure in the "big tasks" you have to solve: input
> data, entering values, calculate result, display thingies. These "big
> tasks" you have to subdivide in "small steps" you can handle in state
> machines.
>
> BTW: what background on VHDL do you have?
1. before I said that input maximum have a 5 digit (each digit is 4 bit) 
so each number of two number between range 0 to 999. following
a0 op b0
a1a0 op b0
a2a1a0 op b0
a0 op b1b0
a1a0 op b1b0
a0 op b2b1b0
op is + - / *
then a2a1a0, b2b1b0 max is 999
2. I no problem with VHDL but In this project I little confuse for 
input.
I hope you understood my problem.
thanks a lot man

von Lothar M. (lkmiller) (Moderator)


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Ali R. wrote:
> a0 op b2b1b0
That makes it somewhat easier, you can hndle the calculations with an 
integer.

> op is + - / *
How do you display it on the 7seg display?

> but In this project I little confuse for input.
Where does the input come from and more: how do you validate it? If "no 
key" is represented by "1111", then how do you come to a "0000" for a 
zero? Because from "1111" you can get several steps of transistions:


"1111" -> "1011" -> 5ns -> "1001" -> 3ns -> "1000" -> 6ns -> "0000"


So which of this steps is the correct one?

Input is easy that far: you take a 20 bit vector and set it to x"FFFFF". 
Then you  and validate the input vector and start writing at the 
leftmost "nibble" (= 4 bits). Then you validate the next input vector 
digit insert it at the next nibble and so forth. So the input pattern 
looks (in hex numbers) alike this when entering 1 2 3 + 4


FFFFF -> 1FFFF -> 12FFF -> 123FF -> 123AF -> 123A4


And on the display you see (_ = blank) this:


___ -> 1____ -> 12___ -> 123__ -> 123+_ -> 123+4


And when the key = is entered, then you start konverting the numbers to 
integers, perform the desired calculation and convert it back in the 
same 20 bits, because those 20 bits are also displayed in the 7seg 
thoughout the whole work.

: Edited by Moderator
von Ali R. (Company: ABC Assembly) (alirahiminezhad)


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Lothar M. wrote:
> Ali R. wrote:

1. op doesn't display on 7Seg and just display input number and result.
2. input comes from the keyboard.
3. in your example "1111" -> "1011" -> 5ns -> "1001" -> 3ns -> "1000" -> 
6ns -> "0000" Should I use freq. divider?
4. I like your suggestion. you're a good man. that's Ok Ill try these 
suggest

von Lothar M. (lkmiller) (Moderator)


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Ali R. wrote:
> input comes from the keyboard.
What kind of keyboard gives you a kind of signal you describe? How do 
you proof, that the input bit pattern from the keyboard is valid?

> Should I use freq. divider?
What should it be good for? You must somehow validate the input value. 
Especially when it comes from a mechanical keyboard and is therefore 
totally asynchronous to the FPGA clock.

> op doesn't display on 7Seg and just display input number and result.
Show some examples of calculatione to get an idea what should happen...

von Ali R. (Company: ABC Assembly) (alirahiminezhad)


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Lothar M. wrote:

> What kind of keyboard gives you a kind of signal you describe? How do
> you proof, that the input bit pattern from the keyboard is valid?
a keyboard or two key for enter 0 , 1

> What should it be good for? You must somehow validate the input value.
> Especially when it comes from a mechanical keyboard and is therefore
> totally asynchronous to the FPGA clock.
In my opinion with some flag I can validate the input value, but I not 
sure

> Show some examples of calculatione to get an idea what should happen...

exp1) input (seven 7-seg := _) : 12+56  1_2_ --> 5_6_
 result (seven 7-seg): (sign)_6_8_

exp2) input (seven 7-seg := _) : 102*3  1_0_2_ --> 3_
 result (seven 7-seg): (sign)_3_0_6_

exp3) input (seven 7-seg := _) : 39*87  3_9_ --> 8_7_
 result (seven 7-seg): (sign)_3_3_9_3_

exp4) input (seven 7-seg := _) : 912-2  9_1_2_ --> 2_
 result (seven 7-seg): (sign)_9_1_0_

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