Input storage in FSM

[yaser fathy]

Hello,

I want to create a fsm that takes a few inputs during its cycle and output these inputs at the end of the cycle .

I wanted to use variables to store these input but the compiler won't accept variable declaration , so I used signals , now the code compiles fine , but the output doesn't show at the end , and the compiler log sais:

output x is assigned by only 2 states
refering to the signal I used to store the input

 

[Rob Gaddi]

On Sun, 10 May 2015 05:47:18 -0700, yaser fathy wrote:

Hello,

I want to create a fsm that takes a few inputs during its cycle and
output these inputs at the end of the cycle .

I wanted to use variables to store these input but the compiler won't
accept variable declaration , so I used signals , now the code compiles
fine , but the output doesn't show at the end , and the compiler log
sais:

output x is assigned by only 2 states refering to the signal I used to
store the input

That sounds like you've made an utter hash of things. I don't know of
any compilers that won't accept VHDL legal variable definitions, so
that's the first sign something's badly wrong. And whatever message
you've got there regarding the output means that your state machine logic
is probably some horrific tangle of combinational and clocked processes.

You want to write the entire thing in a single process. Google for vhdl
single process state machine. You'll get a ton of hits; most of which
will be crap. Spend the time reading through them, valid and crap alike,
until you understand the concept. Be willing to blow an hour on it.

Then, and here's the part you won't like, delete your entire existing
architecture definition. Wipe it out. It's wrong, it's a mess, I can
tell you without even reading it. Even if you manage to cobble together
code that seems to work from it, you'll miss something. It's what, 30
lines of code? 40? Write it fresh with a clear idea of how it should be
structured; you'll get there in half the time. What you've currently got
can only get in your way.

So ends the advice of Rob.

As an aside to the other old farts around here, I was going to point him
to Mike Tressler's site for specific examples, and couldn't find even
archives of it. Anyone still have a reference for it?

--
Rob Gaddi, Highland Technology -- www.highlandtechnology.com
Email address domain is currently out of order. See above to fix.

 

[Andy Botterill]

On 11/05/15 17:59, Rob Gaddi wrote:

On Sun, 10 May 2015 05:47:18 -0700, yaser fathy wrote:


As an aside to the other old farts around here, I was going to point him
to Mike Tressler's site for specific examples, and couldn't find even
archives of it. Anyone still have a reference for it?

This was posted in 2007.

http://home.comcast.net/~mike_treseler/

Unfortunately that URL does not exist any more.

Look at page 31 of this
http://ens.ewi.tudelft.nl/Education/courses/et4351/structured_vhdl.pdf

It does refer to Mike Treseler's code and gives an example.

The powerpoint points to a Verizon place which does not exist as well.

Hopefully Mike will come back.......

 

[Rob Gaddi]

On Mon, 11 May 2015 15:51:29 -0400, rickman wrote:

On 5/11/2015 2:22 PM, Andy Botterill wrote:

Hopefully Mike will come back.......

I don't see where he has posted here since 2013. Searching a bit on the
web uncovers him as being at Microsoft working on the XBox since Dec
2013. So that may explain it. He may be working on a black ops sort of
thing and not allowed to participate in social media.

This is USENET. Who's social?

--
Rob Gaddi, Highland Technology -- www.highlandtechnology.com
Email address domain is currently out of order. See above to fix.

 

[rickman]

On 5/11/2015 2:22 PM, Andy Botterill wrote:

On 11/05/15 17:59, Rob Gaddi wrote:
On Sun, 10 May 2015 05:47:18 -0700, yaser fathy wrote:


As an aside to the other old farts around here, I was going to point him
to Mike Tressler's site for specific examples, and couldn't find even
archives of it. Anyone still have a reference for it?

This was posted in 2007.

http://home.comcast.net/~mike_treseler/

Unfortunately that URL does not exist any more.

Look at page 31 of this
http://ens.ewi.tudelft.nl/Education/courses/et4351/structured_vhdl.pdf

It does refer to Mike Treseler's code and gives an example.

The powerpoint points to a Verizon place which does not exist as well.

Hopefully Mike will come back.......

I don't see where he has posted here since 2013. Searching a bit on the
web uncovers him as being at Microsoft working on the XBox since Dec
2013. So that may explain it. He may be working on a black ops sort of
thing and not allowed to participate in social media.

--

Rick