An integrated circuit is coupled to a communication link and to a separate signal line and includes programmable registers specifying communication link width and frequency. The integrated circuit responds to a change in the value of the signal line by changing the width and/or frequency of at least a portion of the communication link to the programmed value in response to a change in a logical value of the signal line, without the integrated circuit entering a reset state. The width and/or frequency may be changed during a POST routine or during system operation as part of a power management or other system function while maintaining its operational state.