what means the following warning?

[lzh08]

Warning: Replaced VCC/GND feeding tri-state bus Data[0]~7 with an always-enabled tri-state buffer
Warning: Replaced VCC/GND feeding tri-state bus Data[1]~6 with an always-enabled tri-state buffer
Warning: Replaced VCC/GND feeding tri-state bus Data[2]~5 with an always-enabled tri-state buffer
Warning: Replaced VCC/GND feeding tri-state bus Data[3]~4 with an always-enabled tri-state buffer
Warning: Replaced VCC/GND feeding tri-state bus Data[4]~3 with an always-enabled tri-state buffer
Warning: Replaced VCC/GND feeding tri-state bus Data[5]~2 with an always-enabled tri-state buffer
Warning: Replaced VCC/GND feeding tri-state bus Data[6]~1 with an always-enabled tri-state buffer
Warning: Replaced VCC/GND feeding tri-state bus Data[7]~0 with an always-enabled tri-state buffer

 

[Iouri]

can you poest youu code, please what device are using, what vendor???/


Regards,

 

[lzh08]

use device ep1c12q240c8
library ieee;
use ieee.std_logic_1164.all;

ENTITY MCU IS
PORT
(
nDataStrobe : IN Std_Logic;
nAddrStrobe : IN Std_Logic;
nWri : IN Std_Logic;
nReset : IN Std_Logic;
Data : INOUT Std_Logic_Vector(7 DOWNTO 0);
nWait : OUT Std_Logic; (nWait)
nAck : OUT Std_Logic;

SysClk : in Std_Logic;
Reset : in Std_Logic
END MCU;

ARCHITECTURE Action OF MCU IS
TYPE State IS (Idle, DataRead, DataWrite, AddrRead, AddrWrite,
DataReadEnd, DataWriteEnd, AddrReadEnd, AddrWriteEnd);
SIGNAL Cur_State, Next_State:State := Idle;
SIGNAL RegDataTemp : std_logic_vector(7 downto 0);
SIGNAL RegAddrTemp : std_logic_vector(7 downto 0);

BEGIN
DataDeal : PROCESS(Cur_State, nDataStrobe, nWri, nAddrStrobe, Data,
RegDataTemp, RegAddrTemp)
begin
nWait <= '0';
Next_State <= Cur_State;
RegDataTemp <= (OTHERS => '0');
RegAddrTemp <= (OTHERS => '0');
Data <= (OTHERS => '0');
case Cur_State is
when Idle => nWait <= '0';
if ((nWri = '1') and (nDataStrobe = '0')) then
Next_State <= DataRead;
elsif ((nWri = '0') and (nDataStrobe = '0')) then
Next_State <= DataWrite;
elsif ((nWri = '1') and (nAddrStrobe = '0')) then
Next_State <= AddrRead;
elsif ((nWri = '0') and (nAddrStrobe = '0')) then
Next_State <= AddrWrite;
else
Next_State <= Idle;
end if;
when DataRead => Data <= RegDataTemp;
nWait <= '1';
Next_State <= DataReadEnd;
when DataWrite => RegDataTemp <= Data;
nWait <= '1';
Next_State <= DataWriteEnd;
when AddrRead => Data <= RegAddrTemp;
nWait <= '1';
Next_State <= AddrReadEnd;
when AddrWrite => RegAddrTemp <= Data;
nWait <= '1';
Next_State <= AddrWriteEnd;
when DataReadEnd => if (nDataStrobe = '1') then
nWait <= '0';
Next_State <= Idle;
else
Next_State <= DataReadEnd;
end if;
when AddrReadEnd => if (nAddrStrobe = '1') then
nWait <= '0';
Next_State <= Idle;
else
Next_State <= AddrReadEnd;
end if;
when DataWriteEnd => if ((nWri = '1') and (nDataStrobe = '1') ) then
nWait <= '0';
Next_State <= Idle;
else
Next_State <= DataWriteEnd;
end if;
when AddrWriteEnd => if ((nWri = '1') and (nAddrStrobe = '1') ) then
nWait <= '0';
Next_State <= Idle;
else
Next_State <= AddrWriteEnd;
end if;
when others => Next_State <= Idle;
end case;
end process;

Sync: process(Reset, SysClk) --检测系统时钟信号SysClk的上升沿
begin
if Reset = '0' then
Cur_State <= Idle;
elsif Rising_Edge(SysClk) then
Cur_State <= Next_State;
end if;
end process;
end Action;

 

[alba800]

if you want to write something from an external bus into the DATA vector you have to put it into three state, using some direction control signals that disables DATA outputs.
eg:
if (wr= active )then
data<="ZZZZZZZZ";
otherwise the DATA output buffers are always enabled and you get a conflict


bye