The dedicated hardware resources of AMD FPGAs efficiently support a large number of design clocks. An external board component usually generates these clocks. These clocks usually enter the device through an input port.
You can also generate clocks using special primitives called clock modifying blocks (CMBs), such as:
- MMCM
- PLL
- BUFR
You can also transform clocks using regular cells such as LUTs and registers. The following sections describe how to define clocks based on where they originate.