Abstract: Provided is a physical layer circuit. Upon detecting a connection recognition signal from an output of a differential input terminal, a first detection circuit outputs a first control signal for allowing an upper layer to output a power supply control signal for turning on a power supply of each of a receiver circuit and a recovery conversion circuit. Upon detecting “input absent” based on the bit configuration of parallel data, a second detection circuit outputs a second control signal for allowing the upper layer to output the power supply control signal for turning off the power supply of each of the receiver circuit and the recovery conversion circuit. A control circuit turns off a power supply of the first detection circuit when the second detection circuit detects “input present”, and turns on the power supply of the first detection circuit when the second detection circuit detects “input absent”.

Abstract: Provided is a physical layer circuit. Upon detecting a connection recognition signal from an output of a differential input terminal, a first detection circuit outputs a first control signal for allowing an upper layer to output a power supply control signal for turning on a power supply of each of a receiver circuit and a recovery conversion circuit. Upon detecting “input absent” based on the bit configuration of parallel data, a second detection circuit outputs a second control signal for allowing the upper layer to output the power supply control signal for turning off the power supply of each of the receiver circuit and the recovery conversion circuit. A control circuit turns off a power supply of the first detection circuit when the second detection circuit detects “input present”, and turns on the power supply of the first detection circuit when the second detection circuit detects “input absent”.

Abstract: A FIFO memory device for use in data transfer between data processing apparatuses having different data bus widths, has an input circuit 11 with a data bus width of k bits, an output circuit 12 with a data bus width of N×k bits (where N>1) that outputs data within the FIFO memory device, a writing pointer 2 that points to a data writing address of the FIFO memory device, a reading pointer 4 that points to a data reading address of the FIFO memory device, and a valid/invalid indicating circuit 6 that indicates whether or not data output to the output circuit 12 is valid.

Abstract: A communication LSI device includes a state machine section and a test control section. The state machine section carries out a configuration operation in an idle state in response to a first reset signal. The state machine section changes to the idle state after completion of the configuration operation. The state machine section outputs a flag signal after a predetermined time since the state machine section changes to the idle state. The test control section outputs one the first reset signal to the state machine section in a test mode in response to the flag signal or a second reset signal externally supplied.

Abstract: In a modulation/demodulation system for an infrared data communication, a three-bit serial-to-parallel converting circuit captures an input signal in units of three bits in synchronism with an input clock, and outputs a three-bit parallel data to a decoder. This decoder converts the three-bit parallel data into a four-bit parallel data having different patterns corresponding to all different patterns of the three-bit parallel data in a one-to-one relation. In this four-bit parallel data, regardless of how the four-bit parallel data are serially arranged, the total length of the continuing “1” bits is two bits at maximum, and the total length of the continuing “0” bits is six bits at maximum. A four-bit parallel-to-serial converting circuit receives the four-bit parallel data, to serially output a serial data in synchronism with a modulation clock. Thus, the data transfer rate can be elevated in the infrared data communication.