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Old 02-28-2006, 03:05 PM
Marco T.
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Default conv_integer

Hallo,
how much clock cycles takes a conv_integer operation?

Many Thanks
Marco


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Old 02-28-2006, 03:11 PM
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Default Re: conv_integer

You cannot calculate with "clock cycles" when using conversion
functions.
Conversion functions and the corresponding data formats are dissolved
by the synthesis tool during synthesis process
so that in the end (real hardware) everything is implemented in
std_logic/std_logic_vector.

Use "to_integer" with library "ieee.numeric_std.all"
instead of conv_integer.

Rgds
André

> Hallo,
> how much clock cycles takes a conv_integer operation?
>
> Many Thanks
> Marco


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  #3 (permalink)  
Old 02-28-2006, 03:15 PM
Marco T.
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Default Re: conv_integer


<[email protected]> wrote in message
news:[email protected] oups.com...
You cannot calculate with "clock cycles" when using conversion
functions.
Conversion functions and the corresponding data formats are dissolved
by the synthesis tool during synthesis process
so that in the end (real hardware) everything is implemented in
std_logic/std_logic_vector.

Use "to_integer" with library "ieee.numeric_std.all"
instead of conv_integer.

Rgds
André

> Hallo,
> how much clock cycles takes a conv_integer operation?
>
> Many Thanks
> Marco



What is the difference between "to_integer" and "conv_integer"?


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  #4 (permalink)  
Old 02-28-2006, 03:27 PM
Michael Schöberl
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Default Re: conv_integer

> What is the difference between "to_integer" and "conv_integer"?

they are from different libraries ...

you should use numeric_std, you should *not* use std_logic_unsigned or
std_logic_signed, for reasons see:
http://www.vhdl.org/comp.lang.vhdl/FAQ1.html


overview of conversion functions:
http://dz.ee.ethz.ch/support/ic/vhdl...ources.en.html

tricks and examples of the numerics:
http://www.synthworks.com/papers/vhd...mapld_2003.pdf


bye,
Michael
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  #5 (permalink)  
Old 02-28-2006, 03:58 PM
John Adair
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Default Re: conv_integer

Marco

This is only a VHDL function defined in a library. Effectively it in itself
is instant. Your speed, frequency, or number of clocks will be determined by
the functions arround it and how data is used.

John Adair
Enterpoint Ltd. - Home of Raggesdtone1. The $90 Spartan-3 Development Board.
http://www.enterpoint.co.uk

"Marco T." <[email protected]> wrote in message
news:[email protected]
> Hallo,
> how much clock cycles takes a conv_integer operation?
>
> Many Thanks
> Marco
>



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