wave-gen.scr

design compile synthesis user guide

/************************************************************************/
/*				Waveform Generator 			*/
/************************************************************************/
/* This example shows how to use the previous example's ROM to		*/
/* implement a waveform generator.					*/
/*  									*/
/* Assume you want to produce the waveform output shown in Figure C-3	*/
/* in appendix C of the VHDL Compiler reference manual. First, declare  */
/* a ROM which is wide enough to hold the output signals (4 bits) and	*/
/* deep enough to hold all time steps (0 to 12, for a total of 13).   	*/
/* Next, define the ROM so that each time step is represented by an 	*/
/* entry in the ROM. Finally, create a counter which cycles through the	*/
/* time steps (ROM addresses), outputting the waveform at each time 	*/
/* step. 								*/
/*  									*/
/* The VHDL code implementing this example is wave-gen.vhd		*/
/*  									*/
/* Note in the code that when STEP reaches the end of the ROM it stops,	*/
/* outputting the last value, until a reset.  To make the sequence 	*/
/* automatically repeat, remove this statement and use instead its 	*/
/* following (commented) statement.					*/
/*  									*/
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/************************************************************************/
/*  									*/
/* To try this example, the following commands would be run:		*/
/* First, set up the path to the libraries. To use a different 		*/
/* technology library, these variables may be changed. 			*/
/*  									*/
/************************************************************************/

search_path = { ., synopsys_root + /libraries/syn}
target_library = {class.db}
symbol_library = {class.sdb}
link_path = {class.db}

/************************************************************************/
/*  									*/
/* The read command is used to read in the VHDL source file.	 	*/
/*  									*/
/*	The read command is described in the Design Compiler Command	*/
/* 	Reference Manual.						*/
/*  									*/
/************************************************************************/

read -format vhdl wave-gen.vhd

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/*  									*/
/* The second step is to set up the process environment. This includes 	*/
/* defining the wire load model and the operating conditions. 		*/
/*  									*/
/*	These commands are described in the Design Compiler Command	*/
/* 	Reference Manual.						*/
/*  									*/
/************************************************************************/

set_wire_load "10x10"
set_operating_conditions WCCOM

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/*  									*/
/* Next, set up the conditions at the boundry of the design. This 	*/
/* includes defining the drive level on the input signals, the load on 	*/
/* the outputs, and the arrival times of the input signals.		*/
/*  									*/
/*	These commands are described in the Design Compiler Command	*/
/* 	Reference Manual.						*/
/*  									*/
/************************************************************************/

set_arrival .1 RESET 
set_drive 1 all_inputs()
set_load 4 all_outputs()

/************************************************************************/
/*  									*/
/* Now, the constraints are specified. In this example, we want the 	*/
/* smallest circuit possible. This is specified as shown below.		*/
/*  									*/
/*	This command is described in the Design Compiler Command	*/
/* 	Reference Manual.						*/
/*  									*/
/************************************************************************/

max_area 0

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/*  									*/
/* Next, the following command will compile this design			*/
/*									*/
/*	Chapter 5 of the Design Compiler Reference manual describes	*/
/*	the compile command and the different options available.	*/
/*  									*/
/************************************************************************/

compile

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/*  									*/
/* 	The design is now compiled. To view the schematic, click on 	*/
/* the 'view' button in the Design Compiler Main Menu, or execute	*/
/* the following commands from the dc_shell command line. 		*/
/*  									*/
/* dc_shell> gen -sort							*/
/* dc_shell> view							*/
/*  									*/
/*	The report command may be used to find the size and speed of 	*/
/* the design. Selecting the 'Report' button from the Main menu will 	*/
/* display the report types available. The Design Compiler Reference 	*/
/* Manual describes all the available reports. From the dc_shell 	*/
/* command line, a report is generated as shown below.			*/
/*  									*/
/* dc_shell> report -area						*/
/* dc_shell> report -timing						*/
/*  									*/
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