Extracting digits [0-9] from an number/integer

[--mms]

Hi:


I would like to know if there is any function/method, in VHDL, to
extract the digits of an integer.

What I wish to do is take, for example, an integer like 2043, and
extract first the number '3', then '4', '0', and '2'.

Each digit will then be converted to a std_logic_vector(3 downto 0).



Thank you!,
m m s

 

[jeppe]

You need to concider a binary to BCD conversion.
The best way to perform this will an old trick from the 60ies I believe involving a slithlig modified shiftregister.

The method can be found here:
http://www.jjmk.dk/MMMI/Lessons/06_Arithmetics/No6_Conversion/Index.htm
Your welcome
Jeppe

 

[m__ m___s]

Thank you. It seems that is what I was looking for.

It is an integer signal that holds the "i" of a counter. The counter
goes from 0 to 2046. I needed each digit separately to display it on
the LCD screen that has the Spartan-3A board.


--m m _s[/QUOTE]

 

[rickman]

Thank you. It seems that is what I was looking for.

It is an integer signal that holds the "i" of a counter. The counter
goes from 0 to 2046. I needed each digit separately to display it on
the LCD screen that has the Spartan-3A board.

There is more than one way to skin a cat. If you are incrementing the
counter, then you can just form a BCD counter and increment that.
That is likely going to use fewer resources than the conversion
code.

Rick

 

[jeppe]

More then one way to skin a cat ....

I agree - it will properly cost you less logic if you implement a binary counter and a BCD counter as well

Jeppe

 

[Victor]

Hi:

I would like to know if there is any function/method, in VHDL, to
extract the digits of an integer.

What I wish to do is take, for example, an integer like 2043, and
extract first the number '3', then '4', '0', and '2'.

Each digit will then be converted to a std_logic_vector(3 downto 0).

Thank you!,
m m  s

you can have 4 counters for each integer.
each can advanced 1 when the before one reached 10.

 

[m m]

http://www.mikrocontroller.net/attachment/19220/D3.1_Binary2BCD.ppt.pdf


(...)

 

[Mike Treseler]

I would like to know if there is any function/method, in VHDL, to
extract the digits of an integer.

What I wish to do is take, for example, an integer like 2043, and
extract first the number '3', then '4', '0', and '2'.

Each digit will then be converted to a std_logic_vector(3 downto 0).

http://en.wikipedia.org/wiki/Binary-coded_decimal