EPROM (including built-in MCU) works at a power supply voltage, but higher voltage must be added to write programs. This higher voltage is the programming voltage.

EPROM is a computer memory chip invented by Israeli engineer Dov Frohman, which can keep data-non-volatile-after power failure. It is a group of floating-gate transistors, which are programmed by an electronic device, and the voltage provided by the device is higher than that commonly used in electronic circuits. Once programmed, EPROM can only be erased by strong ultraviolet radiation. EPROM can be easily identified through the transparent window on the top of the package, which is also used for ultraviolet erasure. You can aim the glass window of EPROM at the direct sunlight for a period of time, and then erase it.