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How to store a matrix in a ROM in VHDL?

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lgdly

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Hello, I am using an asynchronous-read ROM, to store a matrix.

It has to be parametrizable, so the columns and rows have to be defined by generics.

I was wondering how I can store something of a different type in each address. I have only previously stored a binary number at each address in the ROM.

However now, I would like to store an actual matrix at each address.

The matrix will have H Rows by M Columns.

Thanks
 

What FPGA allows asynchronous read access to a memory, I can't think of any part that allows that. Xilinx, Altera, Microsemi, Lattice memories all have synchronous memory, i.e. the memory has a clock input.

If you want to store a 16x8 matrix you organize the memory index by making say bits 2 downto 0 of the address the column (8 columns) and the row would be 6 downto 3 for 16 rows. If you have something non-binary then you'll have to deal with modulo addressing.
e.g. for a 4x3 matrix
mem(0) = M(0,0)
mem(1) = M(0,1)
mem(2) = M(0,2) <<<< mod 3
mem(3) = M(1,0)
...
mem(10) = M(4,2)
mem(11) = M(4,3)
It might be easier to avoid that and just store it with a 4x4 arrangement throwing away the mem(#,3) locations.
 

ads-ee said:
What FPGA allows asynchronous read access to a memory, I can't think of any part that allows that. Xilinx, Altera, Microsemi, Lattice memories all have synchronous memory, i.e. the memory has a clock input.
Click to expand...

It's not going to be synthezised, only simulated.

And thank you for your suggestion that's how I will implement it.
 

lgdly said:
It's not going to be synthezised, only simulated.

And thank you for your suggestion that's how I will implement it.
Click to expand...

If it's not going to be synthesised, why bother with a ram at all? just use a 2D array.
 

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