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Old 02-20-2004, 03:42 PM   #1
Default VHDL Compilation error. Please help


Hello,
I'm quite new to VHDL. I need to write VHDL code for a vending machine
as part of my assignment.

I get the following errors.
# Error: ELBWRITE_0028: vendingMachine.vhd : (199, 0):
Signal "Number_Of_Cans" has two sources, but is not
resolved signal (at line 199: Number_Of_Cans & at line
46: Number_Of_Cans).
# Error: ELBWRITE_0028: vendingMachine.vhd : (200, 0):
Signal "Next_State" has two sources, but is not
resolved signal (at line 200: Next_State & at line 58:
Next_State).
# Error: ELBWRITE_0028: vendingMachine.vhd : (241, 0):
Signal "Number_Of_Bottles" has two sources, but is not
resolved signal (at line 241: Number_Of_Bottles & at
line 45: Number_Of_Bottles).

Can someone please throw some light on these errors & any other
comments on the following code is greatly appreciated.

-------------------------------------------------------
-------------------------------------------------------

Library IEEE;
use IEEE.std_logic_1164.all;

------------------------------
-- Entity Definition
------------------------------

entity CokeMachine is
Port ( CLK : In std_logic ;
Reset_N : In std_logic ;
Money_In : In std_logic_vector ( 0 to 1 ) ;
CBR_Buttons : In std_logic_vector ( 0 to 1 ) ;

Bottle_Out : Out std_logic ;
Can_Out : Out std_logic ;
Refund_10p : Out std_logic ;
Refund_20p : Out std_logic ;
Refund_50p : Out std_logic ;
Refund_All : Out std_logic ;
No_Cans_Left : Out std_logic ;
No_Bottles_Left : Out std_logic ;
Need_More_Money : Out std_logic );
end CokeMachine ;

architecture RTL of CokeMachine is
type State_Type is ( Start, State_10p, State_20p,
State_30p, State_40p, State_50p,
State_60p, State_70p );

signal Current_State : State_Type ;
signal Next_State : State_Type ;

signal Number_Of_Bottles, Number_Of_Cans : integer := 0 ;

begin

State_Clock : process( Reset_N, CLK, Next_State )
begin
if rising_edge( CLK ) then
if Reset_N = '1' then
Current_State <= Start;
Number_Of_Bottles <= 10;
Number_Of_Cans <= 10;
else
Current_State <= Next_State ;
end if;
end if;
end process State_Clock;

Next_State_Control : process( Money_In, Current_State )
begin
case Current_State is
when Start =>
if Money_In = "00" then
Next_State <= Current_State ;
elsif Money_In = "01" then
Next_State <= State_10p ;
elsif Money_In = "10" then
Next_State <= State_20p ;
elsif Money_In = "11" then
Next_State <= State_50p ;
end if ;
when State_10p =>
if Money_In = "00" then
Next_State <= Current_State ;
elsif Money_In = "01" then
Next_State <= State_20p ;
elsif Money_In = "10" then
Next_State <= State_30p ;
elsif Money_In = "11" then
Next_State <= State_60p ;
end if ;
when State_20p =>
if Money_In = "00" then
Next_State <= Current_State ;
elsif Money_In = "01" then
Next_State <= State_30p ;
elsif Money_In = "10" then
Next_State <= State_40p ;
elsif Money_In = "11" then
Next_State <= State_70p ;
end if ;
when State_30p =>
if Money_In = "00" then
Next_State <= Current_State ;
elsif Money_In = "01" then
Next_State <= State_40p ;
elsif Money_In = "10" then
Next_State <= State_50p ;
elsif Money_In = "11" then
Next_State <= Current_State ;
Refund_50p <= '1' ;
end if ;
when State_40p =>
if Money_In = "00" then
Next_State <= Current_State ;
elsif Money_In = "01" then
Next_State <= State_50p ;
elsif Money_In = "10" then
Next_State <= State_70p ;
elsif Money_In = "11" then
Next_State <= Current_State ;
Refund_50p <= '1' ;
end if ;
when State_50p =>
if Money_In = "00" then
Next_State <= Current_State ;
elsif Money_In = "01" then
Next_State <= State_60p ;
elsif Money_In = "10" then
Next_State <= State_70p ;
elsif Money_In = "11" then
Next_State <= Current_State ;
Refund_50p <= '1' ;
end if ;
when State_60p =>
if Money_In = "00" then
Next_State <= Current_State ;
elsif Money_In = "01" then
Next_State <= State_70p ;
elsif Money_In = "10" then
Next_State <= Current_State ;
Refund_20p <= '1' ;
elsif Money_In = "11" then
Next_State <= Current_State ;
Refund_50p <= '1' ;
end if ;
when State_70p =>
if Money_In = "00" then
Next_State <= Current_State ;
elsif Money_In = "01" then
Next_State <= Current_State ;
Refund_10p <= '1' ;
elsif Money_In = "10" then
Next_State <= Current_State ;
Refund_20p <= '1' ;
elsif Money_In = "11" then
Next_State <= Current_State ;
Refund_50p <= '1' ;
end if ;
end case ;
end process ;

Output_Control : process( CBR_Buttons, Current_State )
begin
if CBR_Buttons = "01" and Number_of_Cans = 0 then
No_Cans_Left <= '1' ;
elsif CBR_Buttons = "10" and Number_Of_Bottles = 0 then
No_Bottles_Left <= '1' ;
else
case Current_State is
when Start =>
if CBR_Buttons = "00" and CBR_Buttons = "11" then
-- do nothing ???
elsif CBR_Buttons = "01" or CBR_Buttons = "10"
then
Need_More_Money <= '1' ;
end if;
when State_10p =>
if CBR_Buttons = "00" then
-- do nothing ???
elsif CBR_Buttons = "01" or CBR_Buttons = "10"
then
Need_More_Money <= '1' ;
elsif CBR_Buttons = "11" then
Refund_10p <= '1' ;
end if;
when State_20p =>
if CBR_Buttons = "00" then
-- do nothing ???
elsif CBR_Buttons = "01" or CBR_Buttons = "10"
then
Need_More_Money <= '1' ;
elsif CBR_Buttons = "11" then
Refund_All <= '1' ;
end if;
when State_30p =>
if CBR_Buttons = "00" then
-- do nothing ???
elsif CBR_Buttons = "01" or CBR_Buttons = "10"
then
Need_More_Money <= '1' ;
elsif CBR_Buttons = "11" then
Refund_All <= '1' ;
end if;
when State_40p =>
if CBR_Buttons = "00" then
-- do nothing ???
elsif CBR_Buttons = "01" or CBR_Buttons = "10"
then
Need_More_Money <= '1' ;
elsif CBR_Buttons = "11" then
Refund_All <= '1' ;
end if;
when State_50p =>
if CBR_Buttons = "00" then
-- do nothing ???
elsif CBR_Buttons = "01" then
if Number_Of_Cans > 0 then
Can_Out <= '1' ;
Number_Of_Cans <= Number_Of_Cans - 1 ;
Next_State <= Start ;
else
No_Cans_Left <= '1' ;
end if;
elsif CBR_Buttons = "10" then
Need_More_Money <= '1' ;
elsif CBR_Buttons = "11" then
Refund_All <= '1' ;
end if;
when State_60p =>
if CBR_Buttons = "00" then
-- do nothing ???
elsif CBR_Buttons = "01" then
if Number_Of_Cans > 0 then
Can_Out <= '1' ;
Refund_10p <= '1' ;
Number_Of_Cans <= Number_Of_Cans - 1 ;
Next_State <= Start ;
else
No_Cans_Left <= '1' ;
end if;
elsif CBR_Buttons = "10" then
Need_More_Money <= '1' ;
elsif CBR_Buttons = "11" then
Refund_All <= '1' ;
end if;
when State_70p =>
if CBR_Buttons = "00" then
-- do nothing ???
elsif CBR_Buttons = "01" then
if Number_Of_Cans > 0 then
Can_Out <= '1' ;
Refund_20p <= '1' ;
Number_Of_Cans <= Number_Of_Cans - 1 ;
Next_State <= Start ;
else
No_Cans_Left <= '1' ;
end if;
elsif CBR_Buttons = "10" then
if Number_Of_Bottles > 0 then
Bottle_Out <= '1' ;
Number_Of_Bottles <= Number_Of_Bottles - 1
;
Next_State <= Start ;
else
No_Bottles_Left <= '1' ;
end if;
elsif CBR_Buttons = "11" then
Refund_All <= '1' ;
end if;
end case ;
end if ;
end process ;
end RTL ;


raju
  Reply With Quote
Old 02-20-2004, 04:04 PM   #2
Scott Thibault
 
Posts: n/a
Default Re: VHDL Compilation error. Please help
You cannot schedule values to a signal (i.e. Number_Of_Cans) in more than
one process. You need to put all the logic involved in determining the
value of Number_Of_Cans in a single process.

Forget about resolved signals. Those are for busses and that is not what
you need here.

--Scott Thibault
Green Mountain Computing Systems, Inc.
http://www.gmvhdl.com


"raju" <> wrote in message
news: om...
> Hello,
> I'm quite new to VHDL. I need to write VHDL code for a vending machine
> as part of my assignment.
>
> I get the following errors.
> # Error: ELBWRITE_0028: vendingMachine.vhd : (199, 0):
> Signal "Number_Of_Cans" has two sources, but is not
> resolved signal (at line 199: Number_Of_Cans & at line
> 46: Number_Of_Cans).
> # Error: ELBWRITE_0028: vendingMachine.vhd : (200, 0):
> Signal "Next_State" has two sources, but is not
> resolved signal (at line 200: Next_State & at line 58:
> Next_State).
> # Error: ELBWRITE_0028: vendingMachine.vhd : (241, 0):
> Signal "Number_Of_Bottles" has two sources, but is not
> resolved signal (at line 241: Number_Of_Bottles & at
> line 45: Number_Of_Bottles).
>
> Can someone please throw some light on these errors & any other
> comments on the following code is greatly appreciated.
>
> -------------------------------------------------------
> -------------------------------------------------------
>
> Library IEEE;
> use IEEE.std_logic_1164.all;
>
> ------------------------------
> -- Entity Definition
> ------------------------------
>
> entity CokeMachine is
> Port ( CLK : In std_logic ;
> Reset_N : In std_logic ;
> Money_In : In std_logic_vector ( 0 to 1 ) ;
> CBR_Buttons : In std_logic_vector ( 0 to 1 ) ;
>
> Bottle_Out : Out std_logic ;
> Can_Out : Out std_logic ;
> Refund_10p : Out std_logic ;
> Refund_20p : Out std_logic ;
> Refund_50p : Out std_logic ;
> Refund_All : Out std_logic ;
> No_Cans_Left : Out std_logic ;
> No_Bottles_Left : Out std_logic ;
> Need_More_Money : Out std_logic );
> end CokeMachine ;
>
> architecture RTL of CokeMachine is
> type State_Type is ( Start, State_10p, State_20p,
> State_30p, State_40p, State_50p,
> State_60p, State_70p );
>
> signal Current_State : State_Type ;
> signal Next_State : State_Type ;
>
> signal Number_Of_Bottles, Number_Of_Cans : integer := 0 ;
>
> begin
>
> State_Clock : process( Reset_N, CLK, Next_State )
> begin
> if rising_edge( CLK ) then
> if Reset_N = '1' then
> Current_State <= Start;
> Number_Of_Bottles <= 10;
> Number_Of_Cans <= 10;
> else
> Current_State <= Next_State ;
> end if;
> end if;
> end process State_Clock;
>
> Next_State_Control : process( Money_In, Current_State )
> begin
> case Current_State is
> when Start =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_10p ;
> elsif Money_In = "10" then
> Next_State <= State_20p ;
> elsif Money_In = "11" then
> Next_State <= State_50p ;
> end if ;
> when State_10p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_20p ;
> elsif Money_In = "10" then
> Next_State <= State_30p ;
> elsif Money_In = "11" then
> Next_State <= State_60p ;
> end if ;
> when State_20p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_30p ;
> elsif Money_In = "10" then
> Next_State <= State_40p ;
> elsif Money_In = "11" then
> Next_State <= State_70p ;
> end if ;
> when State_30p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_40p ;
> elsif Money_In = "10" then
> Next_State <= State_50p ;
> elsif Money_In = "11" then
> Next_State <= Current_State ;
> Refund_50p <= '1' ;
> end if ;
> when State_40p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_50p ;
> elsif Money_In = "10" then
> Next_State <= State_70p ;
> elsif Money_In = "11" then
> Next_State <= Current_State ;
> Refund_50p <= '1' ;
> end if ;
> when State_50p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_60p ;
> elsif Money_In = "10" then
> Next_State <= State_70p ;
> elsif Money_In = "11" then
> Next_State <= Current_State ;
> Refund_50p <= '1' ;
> end if ;
> when State_60p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_70p ;
> elsif Money_In = "10" then
> Next_State <= Current_State ;
> Refund_20p <= '1' ;
> elsif Money_In = "11" then
> Next_State <= Current_State ;
> Refund_50p <= '1' ;
> end if ;
> when State_70p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= Current_State ;
> Refund_10p <= '1' ;
> elsif Money_In = "10" then
> Next_State <= Current_State ;
> Refund_20p <= '1' ;
> elsif Money_In = "11" then
> Next_State <= Current_State ;
> Refund_50p <= '1' ;
> end if ;
> end case ;
> end process ;
>
> Output_Control : process( CBR_Buttons, Current_State )
> begin
> if CBR_Buttons = "01" and Number_of_Cans = 0 then
> No_Cans_Left <= '1' ;
> elsif CBR_Buttons = "10" and Number_Of_Bottles = 0 then
> No_Bottles_Left <= '1' ;
> else
> case Current_State is
> when Start =>
> if CBR_Buttons = "00" and CBR_Buttons = "11" then
> -- do nothing ???
> elsif CBR_Buttons = "01" or CBR_Buttons = "10"
> then
> Need_More_Money <= '1' ;
> end if;
> when State_10p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" or CBR_Buttons = "10"
> then
> Need_More_Money <= '1' ;
> elsif CBR_Buttons = "11" then
> Refund_10p <= '1' ;
> end if;
> when State_20p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" or CBR_Buttons = "10"
> then
> Need_More_Money <= '1' ;
> elsif CBR_Buttons = "11" then
> Refund_All <= '1' ;
> end if;
> when State_30p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" or CBR_Buttons = "10"
> then
> Need_More_Money <= '1' ;
> elsif CBR_Buttons = "11" then
> Refund_All <= '1' ;
> end if;
> when State_40p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" or CBR_Buttons = "10"
> then
> Need_More_Money <= '1' ;
> elsif CBR_Buttons = "11" then
> Refund_All <= '1' ;
> end if;
> when State_50p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" then
> if Number_Of_Cans > 0 then
> Can_Out <= '1' ;
> Number_Of_Cans <= Number_Of_Cans - 1 ;
> Next_State <= Start ;
> else
> No_Cans_Left <= '1' ;
> end if;
> elsif CBR_Buttons = "10" then
> Need_More_Money <= '1' ;
> elsif CBR_Buttons = "11" then
> Refund_All <= '1' ;
> end if;
> when State_60p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" then
> if Number_Of_Cans > 0 then
> Can_Out <= '1' ;
> Refund_10p <= '1' ;
> Number_Of_Cans <= Number_Of_Cans - 1 ;
> Next_State <= Start ;
> else
> No_Cans_Left <= '1' ;
> end if;
> elsif CBR_Buttons = "10" then
> Need_More_Money <= '1' ;
> elsif CBR_Buttons = "11" then
> Refund_All <= '1' ;
> end if;
> when State_70p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" then
> if Number_Of_Cans > 0 then
> Can_Out <= '1' ;
> Refund_20p <= '1' ;
> Number_Of_Cans <= Number_Of_Cans - 1 ;
> Next_State <= Start ;
> else
> No_Cans_Left <= '1' ;
> end if;
> elsif CBR_Buttons = "10" then
> if Number_Of_Bottles > 0 then
> Bottle_Out <= '1' ;
> Number_Of_Bottles <= Number_Of_Bottles - 1
> ;
> Next_State <= Start ;
> else
> No_Bottles_Left <= '1' ;
> end if;
> elsif CBR_Buttons = "11" then
> Refund_All <= '1' ;
> end if;
> end case ;
> end if ;
> end process ;
> end RTL ;




Scott Thibault
  Reply With Quote
Old 02-20-2004, 04:05 PM   #3
Cameron, Charles B.
 
Posts: n/a
Default Re: VHDL Compilation error. Please help
raju wrote:

>Hello,
>I'm quite new to VHDL. I need to write VHDL code for a vending machine
>as part of my assignment.
>
>I get the following errors.
># Error: ELBWRITE_0028: vendingMachine.vhd : (199, 0):
>Signal "Number_Of_Cans" has two sources, but is not
>resolved signal (at line 199: Number_Of_Cans & at line
>46: Number_Of_Cans).
># Error: ELBWRITE_0028: vendingMachine.vhd : (200, 0):
>Signal "Next_State" has two sources, but is not
>resolved signal (at line 200: Next_State & at line 58:
>Next_State).
># Error: ELBWRITE_0028: vendingMachine.vhd : (241, 0):
>Signal "Number_Of_Bottles" has two sources, but is not
>resolved signal (at line 241: Number_Of_Bottles & at
>line 45: Number_Of_Bottles).
>
>Can someone please throw some light on these errors & any other
>comments on the following code is greatly appreciated.
>
>-------------------------------------------------------
>-------------------------------------------------------
>
>Library IEEE;
>use IEEE.std_logic_1164.all;
>
>------------------------------
>-- Entity Definition
>------------------------------
>
>entity CokeMachine is
> Port ( CLK : In std_logic ;
> Reset_N : In std_logic ;
> Money_In : In std_logic_vector ( 0 to 1 ) ;
> CBR_Buttons : In std_logic_vector ( 0 to 1 ) ;
>
> Bottle_Out : Out std_logic ;
> Can_Out : Out std_logic ;
> Refund_10p : Out std_logic ;
> Refund_20p : Out std_logic ;
> Refund_50p : Out std_logic ;
> Refund_All : Out std_logic ;
> No_Cans_Left : Out std_logic ;
> No_Bottles_Left : Out std_logic ;
> Need_More_Money : Out std_logic );
>end CokeMachine ;
>
>architecture RTL of CokeMachine is
>type State_Type is ( Start, State_10p, State_20p,
> State_30p, State_40p, State_50p,
> State_60p, State_70p );
>
>signal Current_State : State_Type ;
>signal Next_State : State_Type ;
>
>signal Number_Of_Bottles, Number_Of_Cans : integer := 0 ;
>
>begin
>
> State_Clock : process( Reset_N, CLK, Next_State )
> begin
> if rising_edge( CLK ) then
> if Reset_N = '1' then
> Current_State <= Start;
> Number_Of_Bottles <= 10;
> Number_Of_Cans <= 10;
> else
> Current_State <= Next_State ;
> end if;
> end if;
> end process State_Clock;
>
> Next_State_Control : process( Money_In, Current_State )
> begin
> case Current_State is
> when Start =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_10p ;
> elsif Money_In = "10" then
> Next_State <= State_20p ;
> elsif Money_In = "11" then
> Next_State <= State_50p ;
> end if ;
> when State_10p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_20p ;
> elsif Money_In = "10" then
> Next_State <= State_30p ;
> elsif Money_In = "11" then
> Next_State <= State_60p ;
> end if ;
> when State_20p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_30p ;
> elsif Money_In = "10" then
> Next_State <= State_40p ;
> elsif Money_In = "11" then
> Next_State <= State_70p ;
> end if ;
> when State_30p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_40p ;
> elsif Money_In = "10" then
> Next_State <= State_50p ;
> elsif Money_In = "11" then
> Next_State <= Current_State ;
> Refund_50p <= '1' ;
> end if ;
> when State_40p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_50p ;
> elsif Money_In = "10" then
> Next_State <= State_70p ;
> elsif Money_In = "11" then
> Next_State <= Current_State ;
> Refund_50p <= '1' ;
> end if ;
> when State_50p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_60p ;
> elsif Money_In = "10" then
> Next_State <= State_70p ;
> elsif Money_In = "11" then
> Next_State <= Current_State ;
> Refund_50p <= '1' ;
> end if ;
> when State_60p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= State_70p ;
> elsif Money_In = "10" then
> Next_State <= Current_State ;
> Refund_20p <= '1' ;
> elsif Money_In = "11" then
> Next_State <= Current_State ;
> Refund_50p <= '1' ;
> end if ;
> when State_70p =>
> if Money_In = "00" then
> Next_State <= Current_State ;
> elsif Money_In = "01" then
> Next_State <= Current_State ;
> Refund_10p <= '1' ;
> elsif Money_In = "10" then
> Next_State <= Current_State ;
> Refund_20p <= '1' ;
> elsif Money_In = "11" then
> Next_State <= Current_State ;
> Refund_50p <= '1' ;
> end if ;
> end case ;
> end process ;
>
> Output_Control : process( CBR_Buttons, Current_State )
> begin
> if CBR_Buttons = "01" and Number_of_Cans = 0 then
> No_Cans_Left <= '1' ;
> elsif CBR_Buttons = "10" and Number_Of_Bottles = 0 then
> No_Bottles_Left <= '1' ;
> else
> case Current_State is
> when Start =>
> if CBR_Buttons = "00" and CBR_Buttons = "11" then
> -- do nothing ???
> elsif CBR_Buttons = "01" or CBR_Buttons = "10"
>then
> Need_More_Money <= '1' ;
> end if;
> when State_10p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" or CBR_Buttons = "10"
>then
> Need_More_Money <= '1' ;
> elsif CBR_Buttons = "11" then
> Refund_10p <= '1' ;
> end if;
> when State_20p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" or CBR_Buttons = "10"
>then
> Need_More_Money <= '1' ;
> elsif CBR_Buttons = "11" then
> Refund_All <= '1' ;
> end if;
> when State_30p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" or CBR_Buttons = "10"
>then
> Need_More_Money <= '1' ;
> elsif CBR_Buttons = "11" then
> Refund_All <= '1' ;
> end if;
> when State_40p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" or CBR_Buttons = "10"
>then
> Need_More_Money <= '1' ;
> elsif CBR_Buttons = "11" then
> Refund_All <= '1' ;
> end if;
> when State_50p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" then
> if Number_Of_Cans > 0 then
> Can_Out <= '1' ;
> Number_Of_Cans <= Number_Of_Cans - 1 ;
> Next_State <= Start ;
> else
> No_Cans_Left <= '1' ;
> end if;
> elsif CBR_Buttons = "10" then
> Need_More_Money <= '1' ;
> elsif CBR_Buttons = "11" then
> Refund_All <= '1' ;
> end if;
> when State_60p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" then
> if Number_Of_Cans > 0 then
> Can_Out <= '1' ;
> Refund_10p <= '1' ;
> Number_Of_Cans <= Number_Of_Cans - 1 ;
> Next_State <= Start ;
> else
> No_Cans_Left <= '1' ;
> end if;
> elsif CBR_Buttons = "10" then
> Need_More_Money <= '1' ;
> elsif CBR_Buttons = "11" then
> Refund_All <= '1' ;
> end if;
> when State_70p =>
> if CBR_Buttons = "00" then
> -- do nothing ???
> elsif CBR_Buttons = "01" then
> if Number_Of_Cans > 0 then
> Can_Out <= '1' ;
> Refund_20p <= '1' ;
> Number_Of_Cans <= Number_Of_Cans - 1 ;
> Next_State <= Start ;
> else
> No_Cans_Left <= '1' ;
> end if;
> elsif CBR_Buttons = "10" then
> if Number_Of_Bottles > 0 then
> Bottle_Out <= '1' ;
> Number_Of_Bottles <= Number_Of_Bottles - 1
>;
> Next_State <= Start ;
> else
> No_Bottles_Left <= '1' ;
> end if;
> elsif CBR_Buttons = "11" then
> Refund_All <= '1' ;
> end if;
> end case ;
> end if ;
> end process ;
>end RTL ;
>

You have two processes, Next_State_Control and Output_Control, both of
which modify, for example, Number_Of_Cans. The compiler can't tell
which signal source you really mean to use. I think you would do well
to let Output_Control be in charge of modifying Number_Of_Cans and that
will eliminate the conflict. Likewise for the other signals with
multiple sources. I haven't checked carefully, but for all I know there
may be other sources for these signals, too, aside from the two I
spotted quite readily.

Charles B. Cameron



Cameron, Charles B.
  Reply With Quote
Old 02-20-2004, 07:50 PM   #4
Ralf Hildebrandt
 
Posts: n/a
Default Re: VHDL Compilation error. Please help
raju wrote:


> I get the following errors.
> # Error: ELBWRITE_0028: vendingMachine.vhd : (199, 0):
> Signal "Number_Of_Cans" has two sources, but is not
> resolved signal (at line 199: Number_Of_Cans & at line
> 46: Number_Of_Cans).

You write to the signal "Number_Of_Cans" from more than one process.
Normally this should be avoided.

An exception are tri-state busses, but as you said you are a newbie:
forget this for a while.


Ralf



Ralf Hildebrandt
  Reply With Quote
Old 02-23-2004, 10:22 AM   #5
raju
 
Posts: n/a
Default Re: VHDL Compilation error. Please help
Thanks Folks,
I merged the two processes. It compiles fine now.

Thanks
Raju

Ralf Hildebrandt <Ralf-> wrote in message news:<c17gbh$1f9om7$>...
> raju wrote:
>
>
> > I get the following errors.
> > # Error: ELBWRITE_0028: vendingMachine.vhd : (199, 0):
> > Signal "Number_Of_Cans" has two sources, but is not
> > resolved signal (at line 199: Number_Of_Cans & at line
> > 46: Number_Of_Cans).
>
> You write to the signal "Number_Of_Cans" from more than one process.
> Normally this should be avoided.
>
> An exception are tri-state busses, but as you said you are a newbie:
> forget this for a while.
>
>
> Ralf


raju
  Reply With Quote
Reply

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