1. Vhdl Binary To Integer Converter Temperature Formula
2. Vhdl Binary To Integer Converter Temperature Chart

Convert 8bit binary number to BCD in VHDL. When you consider the combinatorial 'depth' of the binary to BCD conversion, for an FPGA it's 6 LUTs (the 6th an input. Hi all, I try to write VHDL code for multiply a decimal (floating point) number with an integer. For example: I have a set of vector (integer) as the input, f(n)= (12,3,10,7). Then, I want to multiply the input with 0.25. As I know, I need to convert the 0.25 to the binary number. Do I need to convert the input also and how the operation will be write in VHDL?

I need to convert an integer to a binary representation, but I don't know the value of the integer. What should I do?

1 Answer

Your declaration of the signal conv_int is invalid. At first, you cannot use conv_int in the subtype indication on the right side because conv_int is not yet defined. You can use other signals (or objects), e.g. Distance, which are declared before. And will you have to specify a range with to or downto and not just the length of the std_logic_vector, e.g.:

Vhdl Binary To Integer Converter Temperature Formula

But this will not work either, because now the range is not constrained during elaboration because timeIn is not a constant. That means, you have to specify the range of the array type std_logic_vector at 'compile' time.

It would make sense here to have the same range for conv_int as for Distance because you assign conv_int to Distance later on. This declaration will be valid:

Vhdl Binary To Integer Converter Temperature Chart

With this change, your code will analyze and elaborate (compile / synthesize). Now your integer to 'binary' conversion at this line

will work as follows: The integer expression timeIn*340/2 will be evaluated at simulation time / at run-time, then converted to unsigned while truncating the binary representation to conv_int'length bits, and finally converting this to std_logic_vector. Be aware that for timeIn values greater than floor(2**16/170) = 101, the truncation will / may lead to an unexpected Distance.

The code can be further improved:

1. You should avoid the non-standard Synopsys package std_logic_unsigned. Please use the standard IEEE package numeric_std only.

2. You process will be equivalent to the one-liner conv_int <= ... written as an concurrent statement. Because variants will be executed when timeIn changes (and once after startup).

3. You don't need an intermediate signal here, if conv_int is only assigned to the output Distance.

4. The multiplication by 340/2 will be equivalent to the multiplication by 170, as long as timeIn is smaller than 2**31/170. This would be the case due to the above requirements regarding truncation.

Thus, your architecture can be reduced to:

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