Abstract: A semiconductor device is configured so that two or more master devices access a slave device via a bus. The semiconductor device includes: a priority generation circuit that generates a priority based on a transfer amount between a specific master device and a specific slave device; and an arbitration circuit that performs an arbitration based on the priority when competition of the accesses occurs.

Abstract: A semiconductor device is configured so that two or more master devices access a slave device via a bus. The semiconductor device includes: a priority generation circuit that generates a priority based on a transfer amount between a specific master device and a specific slave device; and an arbitration circuit that performs an arbitration based on the priority when competition of the accesses occurs.

Abstract: Provided is a memory system that can specify a cause of an error. According to the memory system, during writing, when write data is looped back, and the write data is an error, the error has occurred between first processing units (51 to 53) or second processing units (56 to 58) and an input/output unit (60). Thus, whether the error has occurred between the first processing units (51 to 53) or the second processing units (56 to 58) and the input/output unit (60), or in a memory (8) can be specified.

Abstract: Multiple data processing circuits may share a semiconductor memory circuit, such as double-data-rate synchronous dynamic random access memory (DDR-SDRAM). A data processing circuit (202-1 or 202-2) ending control of a semiconductor memory circuit (201) supplies a clock enable signal and chip select signal at predetermined levels. A data processing circuit (202-2 or 202-1) starting control of a semiconductor memory circuit (201) supplies a clock enable signal and chip select signal at the same predetermined levels, before the data processing circuit (202-1 or 202-2) ending control stops supplying a clock enable signal and chip select signal. Therefore, a clock enable signal and chip select signal do not enter an undefined state, and malfunctions that could otherwise occur are prevented.

Abstract: A memory controller can accurately synchronize a strobe signal generated from a clock signal with respect to digital data for inputting/outputting digital data to/from a semiconductor memory device, such as double-data-rate (DDR) synchronous dynamic random access memory (SDRAM), or the like. Output holding circuits (108) can be situated adjacent to corresponding data output terminal (105). One of (n/2) output delay circuits (112) can be situated adjacent to every two of n signal output terminals (112). Wiring lengths from output holding circuits (108) to data output terminals (105) can be made essentially equal to wiring lengths between the output of each delay circuit (112) and the corresponding signal output terminals (112). A delay of digital data transmitted from output holding circuits (108) to data output terminals (105) can be made essentially equal to a delay of an output strobe signal transmitted from output delay circuits (112) to corresponding signal output terminals (106).

Abstract: Multiple data processing circuits may share a semiconductor memory circuit, such as double-data-rate synchronous dynamic random access memory (DDR-SDRAM). A data processing circuit (202-1 or 202-2) ending control of a semiconductor memory circuit (201) supplies a clock enable signal and chip select signal at predetermined levels. A data processing circuit (202-2 or 202-1) starting control of a semiconductor memory circuit (201) supplies a clock enable signal and chip select signal at the same predetermined levels, before the data processing circuit (202-1 or 202-2) ending control stops supplying a clock enable signal and chip select signal. Therefore, a clock enable signal and chip select signal do not enter an undefined state, and malfunctions that could otherwise occur are prevented.

Abstract: A PLL circuit of which pull-in time is reduced. The PLL circuit comprises a voltage controlled oscillator; a frequency divider which divides the frequency of the output signal from the voltage controlled oscillator; a phase detector which compares the phase of a standard signal and the frequency-divided signal and outputs an advanced phase signal and a delayed phase signal; a charge pump which charges and discharges a capacitor in a low pass filter, depending upon the advanced/delayed phase signals; a voltage supplier which supplies the control terminal of the voltage controlled oscillator with a voltage which corresponds to the desired voltage decided by the different output frequencies of the voltage controlled oscillator, when the output of the low pass filter is not virtually connected with the control terminal of the voltage controlled oscillator.