Description
Adds or removes resets for specific state variables (global or static).
The reset port is used to restore the registers and block RAM, connected to
the port, to an initial value any time the reset signal is applied. The presence and
behavior of the RTL reset port is controlled using the config_rtl settings. The reset settings include the ability to set the polarity
of the reset, and specify whether the reset is synchronous or asynchronous, but more
importantly it controls, through the reset option, which registers are reset when the reset
signal is applied. For more information, see Controlling the Reset Behavior.
Greater control over reset is provided through the RESET pragma. If a
variable is a static or global, the RESET pragma is used to explicitly add a reset, or the
variable can be removed from the reset by turning off the
pragma. This can be particularly useful when static or global arrays are present in the
design.
Syntax
Place the pragma in the C source within the boundaries of the variable life cycle.
#pragma HLS reset variable=<a> offWhere:
-
variable=<a> - Specifies the variable to which the RESET pragma is applied.
-
off - Indicates that reset is not generated for the specified variable.
Example 1
This example adds reset to the variable a
in function foo even when the global reset setting is
none or control.
void foo(int in[3], char a, char b, char c, int out[3]) {
#pragma HLS reset variable=a Example 2
Removes reset from variable a in function
foo even when the global reset setting is state or all.
void foo(int in[3], char a, char b, char c, int out[3]) {
#pragma HLS reset variable=a off