Command execution data is received. The command execution data comprises a block address corresponding to an functional component, a register identifier corresponding to a design for testability (DFT) register of the functional component, and command data. The command execution data is converted to a serial command. The serial command is committed to the DFT register of the functional component. A response to the serial command is received. The response is generated by the functional component based on the serial command. The response is converted to command response data and is provided to a testing sub-system.