using procedures

I am confused howto make use of procedures. It was my understanding
that i could use wait statements within the body of procedure. Yet my
vhdl code is not being synthesized. Can someone help me with this ? or
give good online reference/tutorial concerning procedures ?

With regards,

Michel Bieleveld.

architecture RTL of ax88796 is
..

Procedure AX_write (AX_reg : in std_logic_vector(9 downto 0);
AX_data : in
std_logic_vector(15 downto 0)) is
begin
Write_ax_loop : loop
..
wait until CLK'EVENT and CLK = '1';
exit Write_ax_loop when nRST = '0';
..
end loop;
end AX_Write;

COMB_PROC: process (CState,Div2ms)
begin
..
AX_Write(reg_dcr,init_dcr);
..
end process;
end RTL;

Michel Bieleveld

Michel Bieleveld a écrit:
> I am confused howto make use of procedures. It was my understanding
> that i could use wait statements within the body of procedure. Yet my
> vhdl code is not being synthesized. Can someone help me with this ? or
> give good online reference/tutorial concerning procedures ?

You cannot call a procedure with wait statements from within a process
with a sensitivity list.


--
____ _ __ ___
| _ \_)/ _|/ _ \ Adresse de retour invalide: retirez le -
| | | | | (_| |_| | Invalid return address: remove the -
|_| |_|_|\__|\___/

Nicolas Matringe

Hmm since i was planning on calling the procedure within my
statemachine I think I have a problem. What I want is to make a
macro?/procedure to easily write values to a registe, do you have any
suggestions to solve my problem ?

How do people generally solve this problem , synchronizing the main
state machine with a write register state machine ?



On Thu, 12 Aug 2004 14:21:12 +0200, Nicolas Matringe
<> wrote:

>Michel Bieleveld a écrit:
>> I am confused howto make use of procedures. It was my understanding
>> that i could use wait statements within the body of procedure. Yet my
>> vhdl code is not being synthesized. Can someone help me with this ? or
>> give good online reference/tutorial concerning procedures ?
>
>You cannot call a procedure with wait statements from within a process
>with a sensitivity list.

Michel Bieleveld

Michel Bieleveld a écrit:
> Hmm since i was planning on calling the procedure within my
> statemachine I think I have a problem. What I want is to make a
> macro?/procedure to easily write values to a registe, do you have any
> suggestions to solve my problem ?
>
> How do people generally solve this problem , synchronizing the main
> state machine with a write register state machine ?

I never use procedures in synthesizable code.
Synchronization of state machines is usually done with signals...
I don't understand what you're trying to do so I can't help you any further
--
____ _ __ ___
| _ \_)/ _|/ _ \ Adresse de retour invalide: retirez le -
| | | | | (_| |_| | Invalid return address: remove the -
|_| |_|_|\__|\___/

Nicolas Matringe

I am trying to improve my coding, what i have till so far is working
nicely. BUT since i need to initialize around 10 registers this would
mean i have to write down 10 * 2 states (like Boot4/Boot5 and
Boot6/Boot7). So now i am confused how to make the code more compact,
and more elegant. ( Like using a procedure)


COMB_PROC: process (CState,Div2ms,AX_Write_Ready,SD_OE)
begin
nCS <= '0';
nBHE <= '0';
case CState is
when Boot1 =>
AX_Write <= '0';
RESET <= '0';
Div2msReset <= '1';
NState <= Boot2;
when Boot2 =>
AX_Write <= '0';
RESET <= '1';
Div2msReset <= '0';
if ( Div2ms = '1') then
NState <= Boot3;
end if;
when Boot3 =>
AX_Write <= '0';
RESET <= '0';
Nstate <= Boot4;

when Boot4 =>
SA <= reg_dcr;
SD_out <= init_dcr;
SD_OE <= '1';
AX_Write <= '1';
Nstate <= Boot5;
when Boot5 =>
AX_Write <= '0';
if (AX_Write_Ready ='1') then
SD_OE <= '0';
NState <= Boot6;
else
SA <= reg_dcr;
SD_out <= init_dcr;
SD_OE <= '1';
end if;
when Boot6 =>
SA <= reg_rbcr0;
SD_out <= init_rbcr0;
SD_OE <= '1';
AX_Write <= '1';
NState <= Boot7;
when Boot7 =>
AX_Write <='0';
if (AX_Write_Ready ='1') then
SD_OE <= '0';
NState <= Boot8;
else
SA <= reg_rbcr0;
SD_out <= init_rbcr0;
SD_OE <= '1';
end if;
when Boot8 =>

end case;
end process;


WRITE_AX: process(CStateW,AX_Write)
begin
case CStateW is
when Write0 =>
nIOWR <= '1';
if (AX_Write='1') then
AX_Write_Ready<= '0';
NStateW <= Write1;
else
AX_Write_Ready<= '1';
end if;
when Write1 =>
nIOWR <= '0';
AX_Write_Ready<= '0';
NStateW <= Write2;
when Write2 =>
nIOWR <= '0';
AX_Write_Ready<= '0';
NstateW <= Write3;
when Write3 =>
nIOWR <= '0';
AX_Write_Ready<= '0';
NstateW <= Write4;
when Write4 =>
nIOWR <= '0';
AX_Write_Ready<= '0';
NstateW <= Write5;
when Write5 =>
nIOWR <= '0';
AX_Write_Ready<= '0';
NStateW <= Write6;
when Write6 =>
AX_Write_Ready<= '0';
nIOWR <= '1';
NstateW <= Write7;
when Write7 =>
AX_Write_Ready<= '0';
nIOWR <= '1';
NstateW <= Write8;
when Write8 =>
AX_Write_Ready<= '0';
nIOWR <= '1';
NStateW <= Write9;
when Write9 =>
AX_Write_Ready<= '0';
nIOWR <= '1';
NstateW <= Write10;
when Write10 =>
AX_Write_Ready<= '0';
nIOWR <= '1';
NStateW <= Write11;
when Write11 =>
AX_Write_Ready<= '0';
nIOWR <= '1';
NstateW <= Write12;
when Write12 =>
AX_Write_Ready <= '0';
nIOWR <= '1';
NStateW <= Write13;
when Write13 =>
AX_Write_Ready<= '0';
nIOWR <= '1';
NStateW <= Write0;
end case;
end process;




end RTL;




On Thu, 12 Aug 2004 15:49:59 +0200, Nicolas Matringe
<> wrote:

>Michel Bieleveld a écrit:
>> Hmm since i was planning on calling the procedure within my
>> statemachine I think I have a problem. What I want is to make a
>> macro?/procedure to easily write values to a registe, do you have any
>> suggestions to solve my problem ?
>>
>> How do people generally solve this problem , synchronizing the main
>> state machine with a write register state machine ?
>
>I never use procedures in synthesizable code.
>Synchronization of state machines is usually done with signals...
>I don't understand what you're trying to do so I can't help you any further

Michel Bieleveld

Michel Bieleveld wrote:

> I am confused howto make use of procedures. It was my understanding
> that i could use wait statements within the body of procedure.

Waits are not allowed for synthesis. See:
http://groups.google.com/groups?q=vh...cedure+lapenta

-- Mike Treseler

Mike Treseler

Michel Bieleveld wrote:

> I am trying to improve my coding, what i have till so far is working
> nicely. BUT since i need to initialize around 10 registers this would
> mean i have to write down 10 * 2 states (like Boot4/Boot5 and
> Boot6/Boot7). So now i am confused how to make the code more compact,
> and more elegant. ( Like using a procedure)

The code looks a tad scary ... 2 asynchronous state machines that send
information back and forth will often give interesting results in the
field. How about giving us the original problem you're trying to solve to
see if we can help you with it?

Regards,

Pieter Hulshoff

Pieter Hulshoff

Yes I thought the code looked scary too Although i *think* the
state machines are well synchronized. However I would love to see some
clean code.

So here is my problem:

I am communicating with another chip. To setup the other chip I need
to make a reset signal of 20ms and then set some registers.

For the communication I need to make a /IOWR pin low for 60ns and high
for at least 100ns. My result were the two main processes listed in my
previous post.

I have no idea to make it more beautiful and would love to hear some
suggestions of how my betters are doing this

With regards,

Michel.


On Thu, 12 Aug 2004 21:31:04 +0200, Pieter Hulshoff
<> wrote:

>Michel Bieleveld wrote:
>
>> I am trying to improve my coding, what i have till so far is working
>> nicely. BUT since i need to initialize around 10 registers this would
>> mean i have to write down 10 * 2 states (like Boot4/Boot5 and
>> Boot6/Boot7). So now i am confused how to make the code more compact,
>> and more elegant. ( Like using a procedure)
>
>The code looks a tad scary ... 2 asynchronous state machines that send
>information back and forth will often give interesting results in the
>field. How about giving us the original problem you're trying to solve to
>see if we can help you with it?
>
>Regards,
>
>Pieter Hulshoff

Michel Bieleveld

"Michel Bieleveld" <> wrote in message
news:...
> Yes I thought the code looked scary too Although i *think* the
> state machines are well synchronized. However I would love to see some
> clean code.
>
> So here is my problem:
>
> I am communicating with another chip. To setup the other chip I need
> to make a reset signal of 20ms and then set some registers.
>
> For the communication I need to make a /IOWR pin low for 60ns and high
> for at least 100ns. My result were the two main processes listed in my
> previous post.
>
> I have no idea to make it more beautiful and would love to hear some
> suggestions of how my betters are doing this
>
> With regards,
>
> Michel.
>
>
> On Thu, 12 Aug 2004 21:31:04 +0200, Pieter Hulshoff
> <> wrote:
>
> >Michel Bieleveld wrote:
> >
> >> I am trying to improve my coding, what i have till so far is working
> >> nicely. BUT since i need to initialize around 10 registers this would
> >> mean i have to write down 10 * 2 states (like Boot4/Boot5 and
> >> Boot6/Boot7). So now i am confused how to make the code more compact,
> >> and more elegant. ( Like using a procedure)
> >
> >The code looks a tad scary ... 2 asynchronous state machines that send
> >information back and forth will often give interesting results in the
> >field. How about giving us the original problem you're trying to solve to
> >see if we can help you with it?
> >
> >Regards,
> >
> >Pieter Hulshoff
>

What I usually do is to use 2 state machines; one FSM takes care of
transferring the data to the external chip, the other (higher level) FSM
takes of what data should be sent. Both communiciate with each other with
signals. The interface to the lower level FSM is for example

data:std_logic_vector(7 downto 0);
start_write:std_logic;
write_done:std_logic;

The first FSM waits for 'start_write' to become '1' and starts the transfer.
When it's done, it sets 'write_done' to '1' and waits for 'start_write' to
become '0' again and sets 'write_done' to '0'. This is a two way handshake.
The higher level FSM just controls these signals.
In this way almostly duplicate logic in states is removed, and has some
analogy of procedures in a procedural language like C.
Depending on some factors, a full two way handshake is not neccessary, and
the control signals can be only one clock pulse wide.

To save even further on states, you can put all the initialisation data in a
big vector and use a counter to select the proper subvector.

Hope this helps,

Jeroen

Jeroen

Michel Bieleveld wrote:
> I am communicating with another chip. To setup the other chip I need
> to make a reset signal of 20ms and then set some registers.
>
> For the communication I need to make a /IOWR pin low for 60ns and high
> for at least 100ns. My result were the two main processes listed in my
> previous post.

Do you have any clock available to your design to synchronize things, and to
measure time with? What frequency is said clock running at?

I agree with Jeroen that it would be good to have one process that
communicates, and one that controls the information that needs to be
communicated. Both should be clocked. I know there are people out there
that have managed to get asynchronous designs working, but it's a
complicated design practice.

Regards,

Pieter Hulshoff

Pieter Hulshoff