General Description: In CPLD design, you can assign a signal to be global set/reset, output enable, or clock by attaching a global attribute. How is this done with Foundation XVHDL? This is documented in Foundation help.
In Foundation Project Manager, click on help->Foundation help contents. The attributes for these global signal are documented in 2 places: 1. Under Techniques, CPLD Design Techniques->Global Nets: Clock, 3-state, Set/Reset.
2. Under Reference, CPLD attribute->CPLD attributes used in VHDL files.
The attributes are set as follows: -- Declare BUFG attribute attribute bufg: string; -- For global clock: attribute bufg of my_clock : signal is "CLK"; -- For global tristate output or output enable attribute bufg of my_enable : signal is "OE"; -- For global set/reset. attribute bufg of my_reset : signal is "SR";