The PD75P036 is a 4-bit signgle-chip microcontroller that replaced the PD75028's on-chip ROM with one-time PROM or EPROM. Because this device can operate at the same supply voltage as its mask version, it is suited for preproduction in development stage or small-scale production. The one-time PROM version is programmable only once and is useful for small-scale production of many different products and time-to-market of a new product. The EPROM version is programmable, erasable, 5