Syn. Warning .

[pradeep]

Hi,

When I synthesised my RAM module in Leonardo spectrum I got the warning as

Warning: Index value 0 to 63 could be out of prefix index constraint 0 to 47.

reg [5:0] ram_slot [0:47] ;
reg [5:0]rd_addr

Always
Begin
:
:
if (read_en)
data_out <= ram_slot [rd_addr] ; ------ WARNING IN THIS LINE
end

How can I overcome this warning?

With regards
Pradeep. G

 

[jools]

Your indexes should be real numbers already assigned i.e to parameters. This
may fix it.

"pradeep" <pradeepg@vlsi1.sastra.edu> wrote in message
news:962c2d3.0403020342.b38b955@posting.google.com...

Hi,

When I synthesised my RAM module in Leonardo spectrum I got the warning as

Warning: Index value 0 to 63 could be out of prefix index constraint 0 to
47.

reg [5:0] ram_slot [0:47] ;
reg [5:0]rd_addr

Always
Begin
:
:
if (read_en)
data_out <= ram_slot [rd_addr] ; ------ WARNING IN THIS LINE
end

How can I overcome this warning?

With regards
Pradeep. G

 

[Andy Peters]

pradeepg@vlsi1.sastra.edu (pradeep) wrote in message news:<962c2d3.0403020342.b38b955@posting.google.com>...

Hi,

When I synthesised my RAM module in Leonardo spectrum I got the warning as

Warning: Index value 0 to 63 could be out of prefix index constraint 0 to 47.

reg [5:0] ram_slot [0:47] ;
reg [5:0]rd_addr

Always
Begin
:
:
if (read_en)
data_out <= ram_slot [rd_addr] ; ------ WARNING IN THIS LINE
end

How can I overcome this warning?

Well, you could start by realizing that you're using a six-bit
address, [5:0], to address the RAM -- that's 64 locations. However,
your memory only has 48 locations. All of this is quite clear from
your code!

You should probably fix this, unless you're damn sure that your
rd_addr counter never exceeds 47.

--a