Systems and methods for controlling the rise and fall times of USB signals for USB devices and peripherals are provided. The rise and fall times of USB peripherals can be controlled, or changed, in order to match the electrical characteristics of the USB peripheral to a USB host. By sweeping through a range of rise and fall times, and testing the reliability of USB output, optimal rise and fall times for the characteristics of a USB peripheral can quickly be determined. In one embodiment, the controllability of the rise and fall times is provided in firmware that changes at least one characteristic of the USB peripheral that affects the amount of current flowing during USB signaling.