Error (10818) Can't infer......

[Altera_Forum]

Hi all, again. 

 I'm trying to follow coding guide lines, but i'm failing with this particular PROCESS call. I can't see how to form the process_button1_handler into anything like the Altera Template examples that allow registers to be properly created.:confused:  I realise that the code for process_button1 is very clunky, that will be reworked later.  In addition, does QII have a predefined TRUE and FALSE?  help?   Error (10818): Can't infer register for "button1_go" at keyfob_top.vhd(52) because it does not hold its value outside the clock edge. Error (10818): Can't infer register for "process_button1_handler:counter" at keyfob_top.vhd(52) because it does not hold its value outside the clock edge . . .   code as follows:   library ieee; use ieee.std_logic_1164.all; entity keyfob_top is port ( pin_clk: in std_logic; -- our input clock pin_button1: in std_logic; -- user button, fires a signal1 pin_led1_output: out std_logic; -- user sees that a button has been pushed pin_ir_output: out std_logic -- IR output signal ); end keyfob_top; architecture led_behaviour of keyfob_top is signal baud_tick : std_logic := '0'; -- baud rate delay signal button1_go : std_logic := '0'; -- start sending button1 press information constant button_up : std_logic := '0'; -- button has not been pressed constant button_down : std_logic :='1'; -- button has been pressed constant led_on : std_logic := '1'; constant led_off : std_logic := '0'; constant true : std_logic := '1'; constant false : std_logic := '0'; begin -- create our baud_rate clock process_baud_clock : process(pin_clk, baud_tick) variable counter1 : integer range 0 to 100 := 0; constant baud_rate : integer := 3; -- baud rate divider begin if(rising_edge(pin_clk)) then -- do we have a new rising edge? counter1 := counter1 + 1; -- incrament the counter if(counter1 > baud_rate) then counter1 := 0; -- reset the counter if(baud_tick = '1') then baud_tick <= '0'; -- toggle state else baud_tick <= '1'; -- toggle state end if; end if; end if; end process process_baud_clock; -- button1 process handler (and debounce) process_button1_handler : process(pin_button1, baud_tick) variable counter : integer range 0 to 100 := 0; constant delay : integer := 3; variable delay_ongoing : std_logic := false; begin -- has a button just been pressed if(rising_edge(pin_button1)) then -- (line52)has button just been pressed delay_ongoing := true; button1_go <= button_down; -- this is a baud tick, continue elsif((delay_ongoing = true)) then -- are we counting a delay? if(counter = 0) then -- button has just been pressed, start counter := counter + 1; elsif(counter = delay)then -- end of debounce, reset everything counter := 0; delay_ongoing := false; button1_go <= button_up; else -- we are in the middle of debounce, continue counter := counter + 1; end if; end if; end process process_button1_handler; -- baud tick handler process_button1 : process(baud_tick, button1_go) variable button1_bits_left : integer range 0 to 10 := 7; -- bits left to transmit for button1 press variable button1_status : std_logic := '0'; begin if(rising_edge(baud_tick)) then if((button1_bits_left < 7) or -- we are already servicing it (button1_go = button_down and button1_bits_left = 7)) then -- start servicing it case button1_bits_left is -- choose which bit to send out when 7 => -- our first bit pin_ir_output <= led_off; pin_led1_output <= led_on; -- show user what is going on when 6 => pin_ir_output <= led_on; when 5 => pin_ir_output <= led_off; when 4 => pin_ir_output <= led_off; when 3 => pin_ir_output <= led_on; when 2 => pin_ir_output <= led_off; when 1 => pin_ir_output <= led_on; when 0 => -- our last bit pin_ir_output <= led_off; pin_led1_output <= led_off; -- show user what is going on --button1_go_write(button_up);-- signal we have finished with teh button press when others => null; end case; if(button1_bits_left > 0) then button1_bits_left := button1_bits_left - 1; -- decrament by one else button1_bits_left := 7; -- reset our bit counter; end if; end if; end if; end process process_button1; end led_behaviour;   yours, in need of help,   bag it.

[Altera_Forum]

Some of your constructs can never work in logic hardwire design, e.g. operating a counter without an edge sensitive condition. (in the second part of process_button1_handler). 

 What update rate do you expect for the counter? Where should it come from?  You can possibly have both ansynchronous and synchronous set for a register value like button1_go. But to be recognized as an asynchronous preset, the condition must take precedence over the synchronous action, but you have reversed the precedence.    --- Quote Start ---  In addition, does QII have a predefined TRUE and FALSE?  --- Quote End ---   VHDL has it for the boolean data type.