Overview of SCC registers
The MCC on the MPS2 or MPS2+ FPGA Prototyping Board writes to the SCC registers in the FPGA at powerup with the values that the configuration board file defines.
During runtime, the MCC polls the LED and switch values to ensure that they match the SCC_CFG1 and SCC_CFG2 register values. The MCC updates the LEDs to match the SCC_CFG1 register values and updates the SCC_CFG2 register to match the user switches.
The SCC_CFG3 register contains board revision information.
The MCC reads the SYS_DLL, SCC_AID and SCC_ID registers to determine whether the PLLs in the FPGA are locked and to determine the loaded FPGA image.