Any programmable device, like a PROM, that can be programmed just once by the end user. However, this term is used almost exclusively to refer to microcontrollers with on-chip PROM.

• 任一可编程的设备，像PROM，仅仅能被最终用户编程一次。然而，这个术语一般被专有地使用在拥有片上PROM的微控制器上。