| Default Parameters Page (Settings Dialog Box) | |
Allows you to add a new default parameter to the current project, or change an existing default parameter.
Global default parameter values and Block Design File (.bdf) Definition instance parameter values do not have an explicitly declared type. In most cases, the Quartus® Prime Standard Edition software can correctly infer the type from the value without ambiguity. For example, "ABC" is interpreted as a string, 123 as an integer, and 15.4 as a floating-point value.
In other cases, such as when the language of the instantiated subdesign is VHDL, the Quartus® Prime Standard Edition software uses the type of the parameter/generic in the instantiated entity to determine how to interpret the value, so that a value of 123 is interpreted as a string if the VHDL parameter uses the string type. In addition, you can set the parameter value in a format that is legal in the language of the instantiated entity. For example, to pass an unsized bit literal value from a Block Design File to Verilog, you can use '1 as the parameter value, and to pass a 4-bit binary vector from a Block Design File to Verilog, you can use 4'b1111 for a parameter of a Verilog entity.
In a few cases, the Quartus® Prime Standard Edition software cannot infer the correct type of a parameter value. To avoid ambiguity, specify the parameter value in a type-encoded format where the first or first and second character of the parameter indicate the type of the parameter, and the rest of the string indicates the value in a quoted sub-string. For example, to pass a binary string 1010 from a Block Design File to Verilog HDL, you cannot simply use the value 1001, because the Quartus® Prime Standard Edition software interprets it as a decimal value. You also can not use the string "1001", because the Quartus® Prime Standard Edition software interprets it as an ASCII string. You must use the type-encoded string B"1001" for the Quartus® Prime Standard Edition software to interpret the parameter value correctly. Altera recommends using the type-encoded format only when necessary to resolve ambiguity.
The table below lists valid parameter strings and the way that each is interpreted by the Quartus® Prime Standard Edition software.
Parameter String |
Quartus® Prime Standard Edition Parameter Type, Format & Value |
|---|---|
S" abc", s" abc" |
String value " abc" |
"abc123", "123abc" |
String value abc123 or 123abc |
F"12.3", f"12.3" |
Floating point number 12.3 |
-5.4 |
Floating point number -5.4 |
D"123", d"123" |
Decimal number 123 |
123, -123 |
Decimal number 123, -123 |
X" ff", H" ff" |
Hexadecimal value FF |
Q"77", O"77" |
Octal value 77 |
B"1010", b"1010" |
Unsigned binary value 1010 |
SB"1010", sb"1010" |
Signed binary value 1010 |
R"1", R"0", R"X", R" Z", r"1", r"0", r"X", r" Z" |
Unsized bit literal |
E"apple", e"apple" |
Enum type, with value apple |
P"1 unit" |
Physical literal, with value (1, unit) |
A(...), a(...) |
Array or record type, whose content is determined by the string (...) |