Since the Reset line is used for clocking the PDI, it is important to bypass or avoid any circuitry that can distort the clock signal during programming or debugging, such as capacitors and external reset sources. During normal operation, the RESET pin has an internal filter to prevent unintentional resets such as those caused by short spikes on the Reset line. Despite the fact that the clock signal is deformed, capacitive loads up to 1 nF have been tested to work with the STK600 and AVR Dragon during programming. Pull-up resistors should be at least 10 kΩ or removed from the Reset line if a Microchip programmer is used.