VHDL Programming

202 Chapter Seven aileron : OUT control; elevator : OUT control); END autopilot; ARCHITECTURE block_level OF autopilot IS COMPON ...

Configurations 203 FOR M2 : hdg_compare USE CONFIGURATION WORK.hdg_comp_con; FOR M3 : hdg_ctrl USE ENTITY WORK.hdg_ctrl(behave); ...

204 Chapter Seven SUMMARY In this chapter, we discussed the following: How default configurations can be used to bind architect ...

Chapter 8 Advanced Topics In this chapter, some of the more esoteric features of VHDL are discussed. Some of the features may be ...

206 Chapter Eight Overloading Overloading allows the designer to write much more readable code. An object is overloaded when the ...

Advanced Topics 207 ELSE result(i) := a(i + 1); END IF; END LOOP; RETURN result; END shiftr; FUNCTION shiftr( a : s_int) return ...

208 Chapter Eight argument(s) type(s) and return type must match for the function to match the call. The third call to function ...

Advanced Topics 209 The types of the parameters can be the same, but the number of parameters can be different. This is shown by ...

210 Chapter Eight result := result + 8; END IF; RETURN result; END convert_addr; END p_addr_convert; This package declares three ...

Advanced Topics 211 supplied in VHDL only work with specific types. For instance, the +opera- tor only works with integer, real, ...

212 Chapter Eight PORT( c : IN INTEGER; PORT( dout : OUT INTEGER); END adder; ARCHITECTURE test OF adder IS SIGNAL internal : IN ...

Advanced Topics 213 PORT( dout : OUT INTEGER); END adder; ARCHITECTURE test2 OF adder IS SIGNAL internal : INTEGER; BEGIN intern ...

214 Chapter Eight ‘ 1 ’, — RX ‘ 0 ’, — F0 ‘ 1 ’, — F1 ‘ 1 ’); — FX BEGIN RETURN nine_2_bit(t); END nine_val_2_bit; FUNCTION “AND ...

Advanced Topics 215 combinations of operator order are covered with three functions, because the function for two inputs of type ...

216 Chapter Eight expression may be required. A qualified expression states the exact type that the expression should attain. Fo ...

Advanced Topics 217 PACKAGE p_qual_2 IS TYPE vector8 IS ARRAY( 0 TO 7) OF BIT; END p_qual_2; USE WORK.p_qual_2.ALL; ENTITY latch ...

218 Chapter Eight make the source being assigned to the signal. Now, whenever the target signal type is changed, the source chan ...

Advanced Topics 219 ATTRIBUTE location : INTEGER; END p_attr; USE WORK.p_attr.ALL; ENTITY board IS PORT( . . . ); END board; ARC ...

220 Chapter Eight The package p_attrdefines the type used for one of the attributes and contains the attribute declarations for ...

Advanced Topics 221 DQ CLK DQ CLK DQ CLK DQ CLK CLK DFFX(0) DFFX(1) DFFX(2) DFFX(3) Z(0) Z(1) Z(2) Z(3) Z(4) A B CLK Figure 8-1 ...