[[Image:Isp headers.svg|thumb|6- and 10-pin AVR ISP headers]]
'''In-system programming''' (ISP), or also called '''in-circuit serial programming''' (ICSP), is the ability of somea [[programmable logic device]]s, [[microcontroller]]s, [[Chipset|chipsetschipset]], andor other [[embedded device]]s to be programmed while installed in a complete system, rather than requiring the chip to be programmed prior tobefore installing it into the system. 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.<ref>[https://www.oreilly.com/library/view/designing-embedded-hardware/0596007558/ch01.html''Oreilly, Designing Embedded Hardware, 2nd Edition by John Catsoulis'']</ref>
