Denso Corporation

Kyouichi Suzuki

Hideaki Ishihara

Naoki Ito

Masahiro Kamiya

Kenji Yamada

Nobutomo Takagi

Toshihiko Matsuoka

Akihiro Sasaki

Yoshinori Teshima

Yuuki Asada

Naoki Itoh

Norio Fujimori

Katsurou Sekiya

A debug circuit of a microcomputer, providing an on-chip debug function, is provided as a measurement permission circuit for outputting a measurement permission signal to a timer that measures, as a measurement object, a time period between two events in a program execution period of the CPU, according to a user-specified condition. The measurement permission circuit includes an interrupt level register for setting an interrupt level that either permits or prohibits a time measurement operation of the timer, and a comparator for determining by comparison a high-low relationship between an interrupt level of an interrupt process executed by the CPU and an interrupt level set in the interrupt level register, and a determination result of the comparator is specified as the measurement permission signal.

Microcomputer

A microcomputer and method are provided capable of restarting a rewrite program without the need for changing a mode using an external terminal when rewriting nonvolatile memory fails. A CPU of a microcomputer executes a rewrite program to clear FLASH status 0 of flash memory and rewrite all areas in it. The CPU finally writes a rewrite completion code to FLASH status 0. The CPU executes a determination program to read FLASH status 0 of the flash memory. The CPU reads ID status information when read data does not match the rewrite completion code. The CPU re-executes the rewrite program when the data matches ID status information.

Microcomputer for flash memory rewriting

During software development, a multichip module is used which encloses a target chip and a development chip in one package. A CPU of the development chip fetches instructions from a flash memory in the chip to execute them, and accesses RAM and peripheral circuits in the chip. For motor control circuits that exist only in the target chip, the CPU accesses them via serial communication. When the one-chip microcomputer operates alone, its CPU switches a switching circuit to a JTAG interface side to actuate a motor control circuit via internal serial communication.

Semiconductor integrated circuit device and microcomputer development supporting device

A microcomputer which is to be utilized in a condition of being built into an apparatus such as a vehicle ECU, includes a ROM having stored therein a program which is prepared by a user and a boot ROM which stores an initialization program for performing at least essential initialization processing which is required for all application programs that will be executed by the microcomputer. The need for the user to generate program contents relating to such initialization processing is thereby eliminated, while increased reliability of operation of the microcomputer is achieved. In addition, it is possible for user-specified initialization data to be read out from a user program and utilized in a part of the initialization processing of the initialization program.

Microcomputer for apparatus control and vehicle-mounted electronic control unit incorporating microcomputer

To provide a microprocessor that can perform high-speed CRC code generation and can be implemented simply and at a low cost, a microprocessor has, at a part of a data input path to a shift circuit which is conventionally installed in an ALU of the microprocessor to execute shift commands, one bit of data that corresponds to the path, an exclusive OR circuit, which computes the exclusive OR of an uppermost bit of byte data and a bit data, is provided. For this circuit, a result according to a generating polynomial such as &lsqb;X,&plus;X,&plus;X,&plus;X,&plus;1&rsqb; is determined on the basis of the installation location of the exclusive OR circuit along the path, and by setting an initial value to the byte data, inputting one bit of the transmission data sequentially to the bit data and operating the shift circuit, a computed result for the CRC code is derived. Consequently, for the microprocessor, the CRC code can be generated at a high speed using the computation commands of the CRC code section. Corresponding techniques for error-checking of received data are also disclosed.

Growing community of inventors

Toyohashi, Japan

Kyouichi Suzuki