key_scan.bdf

程序主要是用硬件描述语言（VHDL）实现： 4*4键盘扫描

/*
WARNING: Do NOT edit the input and output ports in this file in a text
editor if you plan to continue editing the block that represents it in
the Block Editor! File corruption is VERY likely to occur.
*/
/*
Copyright (C) 1991-2004 Altera Corporation
Any  megafunction  design,  and related netlist (encrypted  or  decrypted),
support information,  device programming or simulation file,  and any other
associated  documentation or information  provided by  Altera  or a partner
under  Altera's   Megafunction   Partnership   Program  may  be  used  only
to program  PLD  devices (but not masked  PLD  devices) from  Altera.   Any
other  use  of such  megafunction  design,  netlist,  support  information,
device programming or simulation file,  or any other  related documentation
or information  is prohibited  for  any  other purpose,  including, but not
limited to  modification,  reverse engineering,  de-compiling, or use  with
any other  silicon devices,  unless such use is  explicitly  licensed under
a separate agreement with  Altera  or a megafunction partner.  Title to the
intellectual property,  including patents,  copyrights,  trademarks,  trade
secrets,  or maskworks,  embodied in any such megafunction design, netlist,
support  information,  device programming or simulation file,  or any other
related documentation or information provided by  Altera  or a megafunction
partner, remains with Altera, the megafunction partner, or their respective
licensors. No other licenses, including any licenses needed under any third
party's intellectual property, are provided herein.
*/
(header "graphic" (version "1.3"))
(pin
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	(rect -48 120 120 136)
	(text "INPUT" (rect 133 0 161 9)(font "Arial" (font_size 6)))
	(text "clk" (rect 5 0 19 12)(font "Arial" ))
	(pt 168 8)
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)
(pin
	(input)
	(rect -48 208 120 224)
	(text "INPUT" (rect 133 0 161 9)(font "Arial" (font_size 6)))
	(text "lie[3..0]" (rect 5 0 41 12)(font "Arial" ))
	(pt 168 8)
	(drawing
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)
(pin
	(output)
	(rect 552 48 728 64)
	(text "OUTPUT" (rect 1 0 34 9)(font "Arial" (font_size 6)))
	(text "hang[3..0]" (rect 90 0 139 12)(font "Arial" ))
	(pt 0 8)
	(drawing
		(line (pt 0 8)(pt 52 8)(line_width 1))
		(line (pt 52 4)(pt 78 4)(line_width 1))
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)
(pin
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	(rect 552 104 728 120)
	(text "OUTPUT" (rect 1 0 34 9)(font "Arial" (font_size 6)))
	(text "key_value[3..0]" (rect 90 0 167 12)(font "Arial" ))
	(pt 0 8)
	(drawing
		(line (pt 0 8)(pt 52 8)(line_width 1))
		(line (pt 52 4)(pt 78 4)(line_width 1))
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		(line (pt 78 12)(pt 82 8)(line_width 1))
	)
)
(symbol
	(rect 384 80 544 176)
	(text "read_lie" (rect 5 0 42 12)(font "Arial" ))
	(text "inst1" (rect 8 80 31 92)(font "Arial" ))
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		(pt 0 32)
		(input)
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		(text "clk" (rect 21 27 35 39)(font "Arial" ))
		(line (pt 0 32)(pt 16 32)(line_width 1))
	)
	(port
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		(input)
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		(line (pt 0 48)(pt 16 48)(line_width 3))
	)
	(port
		(pt 0 64)
		(input)
		(text "lie_scan[3..0]" (rect 0 0 66 12)(font "Arial" ))
		(text "lie_scan[3..0]" (rect 21 59 87 71)(font "Arial" ))
		(line (pt 0 64)(pt 16 64)(line_width 3))
	)
	(port
		(pt 160 32)
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		(text "led[3..0]" (rect 99 27 139 39)(font "Arial" ))
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	(drawing
		(rectangle (rect 16 16 144 80)(line_width 1))
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)
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	(rect 160 96 320 192)
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	(port
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		(input)
		(text "CLK" (rect 0 0 21 12)(font "Arial" ))
		(text "CLK" (rect 21 27 42 39)(font "Arial" ))
		(line (pt 0 32)(pt 16 32)(line_width 1))
	)
	(port
		(pt 160 32)
		(output)
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		(text "CNT_OUT[1..0]" (rect 63 27 139 39)(font "Arial" ))
		(line (pt 160 32)(pt 144 32)(line_width 3))
	)
	(port
		(pt 160 48)
		(output)
		(text "CLK_SCAN[3..0]" (rect 0 0 83 12)(font "Arial" ))
		(text "CLK_SCAN[3..0]" (rect 56 43 139 55)(font "Arial" ))
		(line (pt 160 48)(pt 144 48)(line_width 3))
	)
	(drawing
		(rectangle (rect 16 16 144 80)(line_width 1))
	)
)
(connector
	(pt 320 144)
	(pt 344 144)
	(bus)
)
(connector
	(pt 320 128)
	(pt 384 128)
	(bus)
)
(connector
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	(bus)
)
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(connector
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(connector
	(pt 384 112)
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(connector
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(connector
	(pt 376 88)
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)
(connector
	(pt 152 128)
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)
(connector
	(pt 152 128)
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)
(connector
	(pt 120 128)
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(connector
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(connector
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(junction (pt 152 128))