Hallo Simon,
do you have also a clock event?
first I see
if (rdy /= '1') then
wait until rdy = '1';
else
wait for 0 ns;
end if;
this is simplify
wait until rdy='1';
Hier you will get an glitch. ack is high for short time but
wait_for_transaction can not see this short event. The signal ack is
only 0ns high.
-- Find start of xaction
ack <= '1';
if (rdy /= '1') then
wait until rdy = '1';
else
wait for 0 ns;
end if;
ack <= '0';
procedure wait_for_transaction ( signal rdy : in std_logic;
signal ack : out std_logic
) is
variable ack_time : time;
begin
-- Done
ack <= '1';
ack_time := now;
-- Find start of xaction
if (rdy /= '1') then
wait until rdy = '1';
else
wait for 0 ns;
end if;
-- Model is active and has taken over contents of record
ack <= '0';
end procedure wait_for_transaction;
Am 10.10.2016 um 09:44 schrieb Simon Thijs de Feber:
> For some stupid reason I am not able to replicate the error anymore.
> I have since changed my code to make it work and proceed.
> It seems these changes had positive effect on the behaviour :(
>
> @Rene
>
> These are the procedures :
>
> [code]
>
> procedure request_transaction ( signal rdy : out std_logic;
> signal ack : in std_logic
> ) is
> begin
>
> -- Record contains new xaction
> rdy <= '1';
> -- Ack = '0', model has started
> wait until ack = '0';
> -- Remove xaction request
> rdy <= '0';
> -- Model executes xaction
> --
> -- Wait for xaction done
> wait until ack = '1';
>
> end procedure request_transaction;
>
>
>
> procedure wait_for_transaction ( signal rdy : in std_logic;
> signal ack : out std_logic
> ) is
> variable ack_time : time;
> begin
>
> -- Done
> ack <= '1';
> ack_time := now;
>
> -- Find start of xaction
> if (rdy /= '1') then
> wait until rdy = '1';
> else
> wait for 0 ns;
> end if;
>
> -- Model is active and has taken over contents of record
> ack <= '0';
>
> end procedure wait_for_transaction;
>
> [/code]
>
> Basic idea behind it is to use transactions and handshake via these 2
> procedures.
>
> best regards,
>
> Simon
>
>
>
>
>
>
>
>
>
>
>
>
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