Tristate-Master-Slave testbench description

[ALuPin]

Hi ,
I want to use the following component instantiation
in my VHDL testbench:



entity tb_test is
end tb_test;

architecture testbench of tb_test is


component test
port ( Reset : in std_logic;
Clk : in std_logic;
Bidir_data : inout std_logic_vector(7 downto 0);
Dir : in std_logic;
Nxt : in std_logic;
Stp : out std_logic
...
);
end component;

signal t_Reset : std_logic;
signal t_Clk : std_logic;
signal t_Bidir_data : std_logic;
signal t_Dir : std_logic;
signal t_Nxt : std_logic;
signal t_Stp : std_logic;
....

signal t_tx_data : std_logic_vector(7 downto 0)
signal t_drive_tx_data : std_logic;

signal t_rx_data : std_logic_vector(7 downto 0);


begin



uut : test
port map ( Reset => t_Reset,
Clk => t_Clk,
Bidir_data => t_Bidir_data,
Dir => t_Dir,
Nxt => t_Nxt,
Stp => t_Stp
);

t_Bidir_data <= t_tx_data when t_drive_tx_data='1' else (others =>
'Z');
t_rx_data <= t_Bidir_data when t_drive_tx_data='0' else (others =>
'0');

process
begin
-- Generate t_tx_data, t_drive_tx_data
-- in this process
end process;


end testbench;



My question :
In the port map
Bidir_data => t_Bidir_data

an INOUT port of the unit under test is connected to a signal within
the testbench.

Will the Tristate Description shown work ? (Which "direction does
"t_Bidir_data" have ?)
The testbench "t_tx_data" generation takes over the tristate bus master
role.


Thank you for your help

Rgds
André

 

[sps]

i guess u won't be able to simulate inout signals....simulator won't
give error but the signal will be missing

 

[Duane Clark]

...
t_Bidir_data <= t_tx_data when t_drive_tx_data='1' else (others =>
'Z');
t_rx_data <= t_Bidir_data when t_drive_tx_data='0' else (others =>
'0');
...

My question :
In the port map
Bidir_data => t_Bidir_data

an INOUT port of the unit under test is connected to a signal within
the testbench.

Will the Tristate Description shown work ? (Which "direction does
"t_Bidir_data" have ?)
The testbench "t_tx_data" generation takes over the tristate bus master
role.

Did you just try it? That would be the easy thing to do. Sure, it will
work. There is normally no reason to tristate the receive data. Just do

t_rx_data <= t_Bidir_data;

 

[ALuPin]

i guess u won't be able to simulate inout signals....simulator won't
give error but the signal will be missing

How can I solve this problem ?
I must simulate inout signals ... Any alternative ?

Rgds
André

 

[Neo]

inout simulations work fine in simulator. just simulate your code.
There is no direction for your "t_Bidir_data". its local to TB.

 

[ALuPin]

Yes, I tried it, and it works.

Thank you for your help )

Rgds
André