1. Digital Design with VHDL
Presented by: Amir Masoud Gharehbaghi

2. Concurrent Statements
Concurrent Signal Assignment
Component Instantiation Statement
Generate Statement
Process Statement
Block Statement
Concurrent Procedure Call Statement
Concurrent Assert Statement

3. Sequential Statements
Signal Assignment Statement
Variable Assignment Statement
IF Statement
Case Statement
Loop Statement
Wait Statement
Procedure Call Statement

4. Sequential Statements (cont.)
Next Statement
Exit Statement
Return Statement
Assertion Statement
Report Statement
Null Statement

5. Block Statement block_label: BLOCK [ (guard_expression) ] [ IS ]
block_header
block_declarative_part
BEGIN
block_statement_part
END BLOCK [ block_label ] ;

6. D-FF Example ARCHITECTURE guarding OF d_ff IS BEGIN
dff_blk: BLOCK (c = ‘1’ AND NOT c’STABLE)
q <= GUARDED d;
END BLOCK;
END guarding;

7. D-FF with block header ARCHITECTURE guarding_h OF d_ff IS BEGIN
dff_blk: BLOCK (c = ‘1’ AND NOT c’STABLE)
PORT(din: IN BIT; qout: OUT BIT);
PORT MAP (din => d; qo => q);
qout <= GUARDED din;
END BLOCK;
END guarding_h;

8. D-FF with enable ARCHITECTURE nested_guard OF d_ff_e IS BEGIN
edge: BLOCK (c = ‘1’ AND NOT c’STABLE)
enable: BLOCK (e = ‘1’ AND GUARD)
q <= GUARDED d;
END BLOCK;
END nested_guard;

9. Resolution Function
FUNCTION anding (drivers: IN BIT_VECTOR) RETURN BIT IS
VARIABLE acc: BIT := ‘1’;
BEGIN
FOR I IN drivers’RANGE LOOP
acc := acc AND drivers(i);
END LOOP;
RETURN acc;
END anding; …
SIGNAL a: anding BIT;
a <= b; a <= c; a <= d;

10. Configuration CONFIGURATION identifier OF entity_name IS
{ use_clause }
FOR architecture_name
{ block_configuration }
END FOR ;
END CONFIGURATION;
block_configuration ::=
FOR block_specification
{ configuration_item }

11. Configuration (cont.) configuration_item ::= block_configuration
| component_configuration
component_configuration ::=
FOR component_specification
[ binding_indication ; ]
[ block_configuration ]
END FOR ;

12. Configuration Example
CONFIGURATION default_c OF test_comp4 IS
FOR customizable
FOR a1: comp4
USE ENTITY WORK.nc4(flexible);
FOR c0, c3: comp1
USE ENTITY WORK.bc1(fixed);END FOR;
FOR c2to3: comp1
USE ENTITY WORK.bc1(fixed); END FOR;
FOR flexible
END FOR;