Abstract: A process program such as an erasing/programming program is stored in a boot mat in a nonvolatile memory operational in a boot mode specified after reset start, and a transfer control program for the process program is also stored therein in advance. With an action of setting control information to a predetermined register as trigger, the state of an on-chip CPU is changed from placed in execution of an optional user program to enabled for execution of a transfer control program in the boot mat, and the CPU is returned to the re-execution state of the optional program, after the process program is transferred to an on-chip RAM.

Abstract: A microcomputer capable of on-board programming of dedicated user communication protocols without requiring a serial interface on the mounted board, and that will not destroy the dedicated user communication protocol code even if the system runs out of control. A user boot mat other than a user mat is provided for programming control programs for the user in the on-chip non-volatile memory of the microcomputer. The user boot mat serves as the mat for programming the dedicated user communication protocol and also provides a user boot mode for running the program. The user boot mat cannot program or erase in this user boot mode. By separating the user boot mat and user mat, an interface capable of programming and erasing the user-specified programming can be achieved without having to program a dedicated communication protocol on the user mat.

Abstract: The present invention provides a microcomputer wherein in a system which needs to respond to events developed at intervals each shorter than an erase/program process time, erase/programming can be effected on an on-chip non-volatile memory as necessary during its processing. An erase and program control program for an electrically erasable and programmable non-volatile memory is configured inclusive of a loop of the application of a high voltage pulse and data verify or the like, for example. If a program jumped to a subroutine for an address specified by a user is programmed in advance during this loop, then a process by a CPU can be temporarily jumped to the subroutine for the user defined address. Thus, erase and programming can be effected on a system which needs to confirm internal and external events every predetermined intervals or a system with a learning function, or the like during the execution of a user program.

Abstract: A microcomputer incorporating a flash memory which is erased and programmed electrically in a stable manner within a relatively wide range of external power supply voltages including those for low-voltage operations. The microcomputer comprises a voltage clamp unit including a reference voltage generating circuit and a constant voltage generating circuit. In operation, the voltage clamp unit generates a voltage of a low dependency on a supply voltage and clamps the generated voltage to a voltage level which, within a tolerable range, is lower than a single supply voltage externally furnished. This prevents voltages boosted by boosting circuits operating on the clamped voltage, i.e., programming and erasure voltages, from being dependent on the externally supplied voltage.

Abstract: The present invention provides a data processing system wherein the waste of use of each storage area by ECC codes is avoided to improve or increase the number of assurances for rewriting of information stored in a non-volatile memory.

Abstract: A microcomputer incorporating a flash memory which is erased and programmed electrically in a stable manner within a relatively wide range of external power supply voltages including those for low-voltage operations. The microcomputer comprises a voltage clamp unit including a reference voltage generating circuit and a constant voltage generating circuit. In operation, the voltage clamp unit generates a voltage of a low dependency on a supply voltage and clamps the generated voltage to a voltage level which, within a tolerable range, is lower than a single supply voltage externally furnished. This prevents voltages boosted by boosting circuits operating on the clamped voltage, i.e., programming and erasure voltages, from being dependent on the externally supplied voltage.

Abstract: A microcomputer incorporating a flash memory which is erased and programmed electrically in a stable manner within a relatively wide range of external power supply voltages including those for low-voltage operations. The microcomputer comprises a voltage clamp unit including a reference voltage generating circuit and a constant voltage generating circuit. In operation, the voltage clamp unit generates a voltage of a low dependency on a supply voltage and clamps the generated voltage to a voltage level which, within a tolerable range, is lower than a single supply voltage externally furnished. This prevents voltages boosted by boosting circuits operating on the clamped voltage, i.e., programming and erasure voltages, from being dependent on the externally supplied voltage.

Abstract: A microcomputer incorporating a flash memory which is erased and programmed electrically in a stable manner within a relatively wide range of external power supply voltages including those for low-voltage operations The microcomputer comprises a voltage clamp unit including a reference voltage generating circuit and a constant voltage generating circuit. In operation, the voltage clamp unit generates a voltage of a low dependency on a supply voltage and clamps the generated voltage to a voltage level which, within a tolerable range, is lower than a single supply voltage externally furnished This prevents voltages boosted by boosting circuits operating on the clamped voltage, i.e., programming and erasure voltages, from being dependent on the externally supplied voltage.

Abstract: A microcomputer incorporating a flash memory which is erased and programmed electrically in a stable manner within a relatively wide range of external power supply voltages including those for low-voltage operations. The microcomputer comprises a voltage clamp unit including a reference voltage generating circuit and a constant voltage generating circuit. In operation, the voltage clamp unit generates a voltage of a low dependency on a supply voltage and clamps the generated voltage to a voltage level which, within a tolerable range, is lower than a single supply voltage externally furnished. This prevents voltages boosted by boosting circuits operating on the clamped voltage, i.e., programming and erasure voltages, from being dependent on the externally supplied voltage.