In-system programming

Writing firmware to an embedded device while it's installed in a system

In-system programming (ISP), or also called in-circuit serial programming (ICSP), is the ability of a programmable logic device, microcontroller, chipset, or other embedded device to be programmed while installed in a complete system, rather than requiring the chip to be programmed before installing. It also allows firmware updates to be delivered to the on-chip memory of microcontrollers and related processors without requiring specialist programming circuitry on the circuit board, and simplifies design work.