Abstract: An oxygen concentration sensor element impedance detecting apparatus and method that maintains sensor detection accuracy by shortening the sweeping time period of an element impedance detecting voltage. A sub-microcomputer performs at least two sweeping actions for switching an element application voltage Vo from a reference voltage to a sweeping voltage when it once detects the element impedance of the oxygen concentration sensor AFS, and A/D converts only one of the element application voltage Vo and an element current detecting voltage Vi during the sweep, to shorten the sweeping time period. A sensor drive circuit prevents the element application voltage Vo from being changed by the element current. Even if element application voltage Vo detection and element current detecting voltage Vi detection are performed by separate sweeps, detection results substantially identical to those of the case in which detection of those two voltages are performed during one sweep are obtained.

Abstract: An engine control apparatus generates a 30° CA signal which rises per 30° CA rotation based on a rotational signal from a crank angle sensor and counts up a value CNT of a crank counter by the 30° CA signal. It also reads the level of a cylinder identification signal from a cam angle sensor every time when a reference position signal within the rotation signal is detected. It initializes the count value to 20 when the read level is low and to 8 when the read level is high. Although the apparatus carries out the cylinder discrimination based on the count value, it is also arranged so as not to initialize the count value when the previously read level is the same with the read level of this time. Thus, the cylinders can be identified correctly even if an abnormality occurs in a sensor for outputting a cylinder identification signal or in its wire.

Abstract: An electronic control unit is provided with a microcomputer, a power supply circuit and a filter circuit. The microcomputer comprises a CPU, a ROM, a RAM and a SRAM. A voltage-drop detecting circuit within the power supply circuit receives a constant voltage generated in a constant voltage circuit and outputs a voltage detection signal WI by monitoring fall of such constant voltage. The filter circuit also receives the WI signal, generates a WI(A) signal and a WI(B) signal and outputs the WI(B) signal to the SRAM as the signal for restricting the data write operation. The CPU allows start of the data write operation to the SRAM and executes the write operation of data for each data that requires the concurrency when both WI(A) and WI(B) signals indicate permission of the data write operation.

Abstract: Only predetermined frequency components included in an ion current flowing between an ignition plug and the ground are extracted from the ion current by means of a low pass filter and a high pass filter as a knock detection signal, that is, a signal used for knock detection. This knock detection signal is then subjected to A/D-conversion in an A/D-converter to generate A/D-converted values which are subsequently supplied to a processing unit employed in a digital signal processor. In the processing unit, the A/D-converted values are subjected to a discrete Fourier transform (DFT) frequency analysis. Knock determination based on data obtained from the DFT frequency analysis results in information indicating the operating state of the internal combustion engine.

Abstract: The resistance of an air-fuel-ratio sensor element is determined from current detected before changing an applied voltage to the sensor and current detected when a predetermined period elapses after changing the applied voltage to the sensor. A resistance detector includes operational amplifiers, resistors and transistors. The applied voltage is changed by switching the transistors to more accurately detect a resistance value.

Abstract: A resistance component of a sensor element for an air-fuel-ratio sensor is determined from a sensor current detected before changing an applied voltage to the sensor and a sensor current detected when a predetermined period elapses after changing the applied voltage to the sensor. A resistance component detecting apparatus includes operational amplifiers, resistors and transistors. The applied voltage is changed by switching the transistors. Accordingly, the resistance component of the sensor element is detected accurately.

Abstract: A method for registering a new key in an anti-theft device allows the registration of a new key having a code type transponder from which authentication data once written cannot be read out or written over. An ECU communicates with a transponder of a registered key such as a master key and allows an engine to be started when the result of a collating function data stored in an EEPROM of the ECU with function data written in the transponder is a match. When function data is to be written into a transponder of an unregistered new key, the ECU first communicates with the transponder of the registered key and, when the result of collation of the function data stored in the EEPROM and the function data written in the transponder of the registered key is a match, writes function data stored in the EEPROM into the transponder of the new key.

Abstract: A DMA control apparatus transfers a data set of bytes, with no intermixing these data bytes and with favorable efficiency. A DMA controller receives data bytes serially and writes this data to a RAM. At this time, when the serially sent data are taken to be made up of data sets where one information item is formed of two bytes, the DMA controller, while temporarily storing data received in odd-numbered order in a data-set adjusting register, controls block write of this together with data received in even-numbered order to the RAM. Due to this, access where data other than these data sets is intermixed is eliminated, even in a case where asynchronous word-unit access of the RAM is performed by the CPU.

Abstract: To execute high-accuracy control employing communication data of a microprocessor while attempting standardization of the microprocessor, a host microprocessor is provided with a ROM, RAM, CPU, and DMA controller, and a KCS microprocessor is provided with a ROM, RAM, CPU, and DMA controller. The host microprocessor and the KCS microprocessor are connected by a bidirectional communication line. At a predetermined cycle, the CPU of the host microprocessor sends data in the ROM relating to the content of control of the KCS microprocessor to the RAM of the KCS microprocessor. Engine information (A/D values and so on) are sent from the KCS microprocessor to the host microprocessor at a cycle of 4 ms, but sending of ROM data from the host microprocessor to the KCS microprocessor is performed during free time in this sending cycle. The ROM data is divided into a plurality of blocks, and the data is sent block by block.

Abstract: A control system adaptable for use in controlling internal combustion engines has a microcomputer and a hardware circuit reconfigurable in internal logic circuitry in such a manner that the setting of configuration is completed before the microcomputer is rendered operative upon application of a power supply voltage. The microcomputer is assembled in a 4-V guarantee circuit block with its operating guarantee power supply voltage of 4 volts. A 3-V guarantee block includes a random logic circuit and an EEPROM for storage of circuit configuration set data. The 3-V guarantee block also includes a first power-on reset circuit for providing respective sections with a reset-release command signal when an applied power supply voltage potentially rises at 3 volts, and a second power-on reset circuit for forcing the random logic circuit in the reset state until completion of the reconfiguration of the hardware circuit.

Abstract: An A/D-converter for a knock determination of an engine performs A/D-conversion with respect to a knock signal having a reference voltage and to another sensor signal having a reference voltage that differs therefrom. When the engine rotation is less than 1000 rpm, since the knock signal is too small to perform malfunction determination, integration of "0" point data (reference voltage: 2.5V) of an integrating circuit is performed within a knock determination time period. The resulting data is A/D-converted by the A/D-converter to thereby update the "0" point value stored in a RAM. On the other hand, in a range of greater than 1000 rpm where malfunction determination can be performed of the knock sensors, within the knock determination time period, the knock signal is integrated using the integrating circuit.

Abstract: A tablet printing machine provided with a roll soiling detecting unit for optically detecting soiling of the surface of a roll of its printing unit. The machine is further provided with a roll cleaning unit including a cleaner to be impregnated with a cleaning liquid and adapted for pressing contact with the transfer roll of the printing unit during the rotation of the roll.