13.32.2.1 Special Characters

Square brackets ([ ]) are special characters in Tcl. To use square brackets in names such as port names, you must either enclose the entire port name in curly braces, for example, pin_assign -port {LFSR_OUT[15]} -iostd lvttl -slew High, or lead the square brackets with a slash (\) character as shown in the following example:

pin_assign -port LFSR_OUT\[15\] -iostd lvttl -slew High