The In-System Programming mode allows the microcontroller to be programmed even after it has been soldered on a printed circuit board. This feature can be used to perform firmware updates at the end of the production line. Typical applications include adding calibration information or installation of the latest software release. In-System programming may also be used during product development as a quick and easy way to modify program code. For example, all P89LPC932 devices are shipped with a factory “boot-loader” which is programmed into the upper 512 bytes of sector seven of the code space. This firmware provides the interface between low-level routines in the device, which perform the requested function (program, erase, etc.), and the serial port. If the user wishes to utilize ISP, care must be taken to not erase or overwrite the code sector containing the ISP firmware (1C00H to 1FFFH). ICP is one of the programming methods of the LPC900 microcontroller family. ICP uses a serial shift protocol that requires five pins to program: PCL, PDA, Reset, VDD and VSS. ICP is different from ISP (In System Programming) because it is done completely by the microcontroller’s hardware and does not require a bootloader. The ICP programming method is a serial programming method, shifting in programming commands and shifting data in and out with a clock and data line.