GENERAL DESCRIPTION
el im This version: Sep. 1998 MSM64P155/64P155L ina Pr ry 4-Bit Microcontroller with Built-in LCD Driver and Melody Circuit On the other hand, the MSM64155 is a mask ROM-version product, which has mask ROM as internal program memory. Unlike the mask ROM-version MSM64155 which has a P-well CMOS structure, the MSM64P155/ 64P155L has been fabricated with the N-well CMOS-structured EPROM process technology. Therefore, the MSM64P155/64P155L differs from the MSM64155 in the polarity of the power supply for LCD bias generation and in the external circuit structure. Unlike the mask ROM-version product, the MSM64P155/64P155L cannot be supplied in the form of a chip. The MSM64P155/64P155L is an OTP-version product used to evaluate an application program. The MSM64P155/64P155L has two operation modes, microcontroller operation mode and PROM mode. The microcontroller operation mode is used to operate the MSM64P155/64P155L like a mask ROM-version product and the PROM mode is used to program or read the PROM.
