guibrain.tdf

MAX+PLUSII教材及实例-西文-152页-1.7M-PDF版.zip

FUNCTION debounce (left_button, right_button, clk)
    RETURNS (debou_left, debou_right, reset, 1Hz, 12Mhz);
    
INCLUDE "lpm_counter.inc";

SUBDESIGN guibrain

(left, right, clk, y_valid : INPUT;
new, sel, cnt_out[4..0], toggle, reset, 12Mhz : OUTPUT;)

VARIABLE
io	: debounce;
cnt[4..0]	: dff;
brain : MACHINE WITH STATES (idle, sel_value, process1, process2, process3);
cnt_ena : NODE;

BEGIN

brain.clk = io.12Mhz;
brain.reset = io.reset;
reset = io.reset;

CASE brain IS
	WHEN idle =>
		IF io.debou_left THEN
		brain = sel_value;
		END IF;
		sel = VCC;  -- DISPLAY = RESULT

	WHEN sel_value =>  
		cnt_ena = VCC;
		-- wait until the right value is picked
		IF io.debou_right THEN  
		brain = process1;
		END IF;
		sel = GND; -- DISPLAY = COUNTER input
		
	WHEN process1 =>
		-- start the process by setting the new =1 
		new = VCC;
		brain = process2;
		sel = GND;  -- DISPLAY = RESULT
	WHEN process2 =>
		IF y_valid THEN -- confirm fir filter is ready for the next input
		brain = process3;
		END IF;
		-- clear the new input 
		new = B"0";
		sel = VCC;  -- DISPLAY = RESULT
	WHEN process3 =>
		IF io.debou_left THEN
		brain = sel_value;
		END IF;
		sel = VCC;  -- DISPLAY = RESULT
END CASE;

-- counter from 0 to 16 for FIR filter input
cnt_out[] = cnt[].q;
cnt[].clrn = !io.reset;
cnt[].clk = io.12Mhz; 
IF cnt_ena & io.debou_left THEN
	IF (cnt[].q == B"10000") THEN
		cnt[] = B"00000";
	else
		cnt[] = cnt[] + 1;
	END IF;
else
	cnt[] = cnt[];
END IF;

-- Connection to and from sub-design debounce.gdf
io.left_button = left;
io.right_button = right;
io.clk = clk;
12Mhz = io.12Mhz;
toggle = io.1hz;

END;