Contextual Info: DATA SHEET NEC MOS INTEGRATED CIRCUIT ZiPD78070A 8-BIT SINGLE-CHIP MICROCONTROLLER DESCRIPTION T h e ¿¿PD78070A is a lim ited-function product from w hich th e internal R O M of th e /iP D 7 8 0 7 8 sub s e rie s h as b e e n rem oved . T hrou gh in te rc h a n g e ab le e xtern al R O M , program m ain ten an ce can be perfo rm ed easily.