{{short description|Type of solid state computer memory that becomes read only after being written once}}
A '''programmable read-only memory''' ('''PROM''') is a form of digital memory where the settingcontents ofcan eachbe bitchanged isonce lockedafter bymanufacture aof [[Fusethe (electrical)|fuse]]device. orThe [[antifuse]]data ([[eFUSE]]sis canthen alsopermanent and cannot be used)changed. It is one type of [[read-only memory]] (ROM). The data in them are permanent and cannot be changed. PROMs are used in digital electronic devices to store permanent data, usually low level programs such as [[firmware]] or [[microcode]]. The key difference from a standard [[Read-only memory|ROM]] is that the data is written into a ROM during manufacture, while with a PROM the data is programmed into them after manufacture. Thus, ROMs tend to be used only for large production runs with well-verified data, while. PROMs aremay be used towhere allowthe companiesvolume torequired testdoes onnot make a subsetfactory-programmed ROM economical, or during development of thea devicessystem inthat anmay orderultimately beforebe burningconverted datato intoROMs allin ofa themmass produced version.
PROMs are manufactured blank and, depending on the technology, can be programmed at wafer, final test, or in system. Blank PROM chips are programmed by plugging them into a device called a ''PROM programmer''. TheCompanies availability of this technology allows companies tocan keep a supply of blank PROMs in stock, and program them at the last minute to avoid large volume commitment. These types of memories are frequently used in [[microcontroller]]s, [[video game console]]s, mobile phones, radio-frequency identification ([[RFID]]) tags, implantable medical devices, high-definition multimedia interfaces ([[HDMI]]) and in many other consumer and automotive electronics products.
