Nippon Telegraph and Telephone Corporation

Sharp Kabushiki Kaisha Corporation

Other

Masaaki Tanno

Tadao Takeda

Kazuhiro Yaegawa

Hiroki Suto

Hiroshi Ban

Nobuhiro Shimoyama

Ryuichi Ogawa

Haruhiko Shigemasa

Masaki Wakabayashi

When a built-in nonvolatile memory in a microcomputer is tested, a control program prestored in a boot ROM is run upon entering a test command from an external communication device; a test program is transferred from the external communication device to a built-in RAM through a communication circuit; a control of a CPU is switched to the built-in RAM after the test program has been transferred and a test is conducted on the nonvolatile memory; and a test result and a fail log are transferred to the external communication device through the communication circuit. Consequently, the built-in nonvolatile memory in the microcomputer can be checked without leaving the test program on the chip.

Microcomputer having built-in nonvolatile memory and check system thereof and IC card packing microcomputer having built-in nonvolatile memory and check system thereof

In order to provide a built-in self testing function, a one-chip microcomputer is equipped with an activation register for activating the test operation and a built-in self test activation pattern generator for setting initial values at test control circuits (pseudo random number generator, logical circuit testing compressor, pattern generator, and memory testing compressor). In accordance with an instruction from the CPU, a built-in self test is activated so that the results of tests of the memory and the group of logical circuits are read from the memory testing compressor and the logical circuit testing compressor, and respectively compared with expected values preliminarily stored in the memory in the one-chip microcomputer; thus, the results are diagnosed. Thus, it is possible to carry out a built-in self test without using a plurality of exclusively-used test terminals.

One-chip microcomputer and control method thereof as well as an IC card having such a one-chip microcomputer

A 1-chip microcomputer having a built-in nonvolatile memory includes at least one erasable flash memory provided in a memory space of the microcomputer, a boot ROM for storing an initial program to start up the 1-chip microcomputer and a transfer program to transfer the initial program to the flash memory, and control means for, when the flash memory stores no program, transferring the initial program to the flash memory in accordance with the transfer program and subsequently removing the boot ROM from the memory space. Consequently, even if a new program is additionally stored to the nonvolatile memory in the 1-chip microcomputer, the additional program can be carried out.

Microcomputer having built-in nonvolatile memory for simultaneous use as a program area and a data area

A semiconductor chip has a nonvolatile memory formed on the upper surface side of a semiconductor substrate. The chip includes at least one recess portion formed in the lower surface of the semiconductor substrate. The recess portion is located in a region corresponding to the nonvolatile memory. A method of manufacturing the semiconductor chip is also disclosed.

Semiconductor chip and method of manufacturing the same

Growing community of inventors

Hadano, Japan

Masaaki Tanno