Syn. warning

[pradeep]

Hi,

When I synthesised my state machine coding in Leonardo spectrum I got
the warning as

Warning: prev_chan not always assigned, storage may be needed.

What does it indicate?

how can i avoid this warnings?

And another warning is

Warning, tpac_size should be present in the 'always' condition

Can any one give the solution for these 2 warnings?

With regards

Pradeep. g

 

[Jim Lewis]

pradeep wrote:

Hi,

When I synthesised my state machine coding in Leonardo spectrum I got
the warning as

Warning: prev_chan not always assigned, storage may be needed.

What does it indicate?

It will create a latch (and you probably don't want this).
Make sure that for every execution path of the always block
that prev_chan gets a value.

how can i avoid this warnings?

And another warning is

Warning, tpac_size should be present in the 'always' condition

Add tpac_size to the sensitivity list.

Cheers,
Jim

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jim Lewis
Director of Training mailto:Jim@SynthWorks.com
SynthWorks Design Inc. http://www.SynthWorks.com
1-503-590-4787

Expert VHDL Training for Hardware Design and Verification
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

[pradeep]

Hi jim,

thank u,

Prev_chan should get a value during a particular state and that value
should be retained till it reaches the same state, so i coded as

prev_chan = chan_num in that state and assigned

prev_chan = prev_chan in all other states, but still i am having the
same problem. can't i code like this.

about the 2nd waring,

always @(tmp_teop)
begin
if (tmp_teop)
begin
if (count < 2'b01)
count_value1 <= tmp_count ;
else
count_value1 <= tmp_count + 17'h00001 ;
end
else
count_value1 <= 17'h00000 ;
end

here even if i include count and tmp_count in the sensitivity list it
will not have any effect unless tmp_teop becomes one, so here i could
avoid unnecessary entry.
Here should i include count and tmp_count in the sensitivity list or
not.

expecting ur guidance

pradeep.g



Jim Lewis <Jim@SynthWorks.com> wrote in message news:<101q93ea27t0hda@corp.supernews.com>...

pradeep wrote:
Hi,

When I synthesised my state machine coding in Leonardo spectrum I got
the warning as

Warning: prev_chan not always assigned, storage may be needed.

What does it indicate?

It will create a latch (and you probably don't want this).
Make sure that for every execution path of the always block
that prev_chan gets a value.


how can i avoid this warnings?

And another warning is

Warning, tpac_size should be present in the 'always' condition

Add tpac_size to the sensitivity list.

Cheers,
Jim

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jim Lewis
Director of Training mailto:Jim@SynthWorks.com
SynthWorks Design Inc. http://www.SynthWorks.com
1-503-590-4787

Expert VHDL Training for Hardware Design and Verification
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~