Abstract: A communication control apparatus, provided with an echo back comparison detecting unit (30) detecting something abnormal of communication data from itself or an abnormal state generated at a data line (4), by starting transmission of communication data from itself following a detection of a line state detecting unit (29), when the line state detecting unit (29) detects that transmission of communication data from another communication apparatus to a data line (4) is started in a transmission permissible section, and by taking in communication data at the data line (4) and by comparing it with communication data having been transmitted from itself, and further provided with a transmission mark generating unit (23) shortening a bit width of data indicating a start of communication data transmitted from itself, prevents an abnormal waveform from being transmitted to the data line (4) because accuracy of echo back comparison is improved and delay tolerance of the data line (4) is eased.

Abstract: A primary object is to provide a communication apparatus, in particular, its buffer memory which conforms mainly to specifications of SAE-J1850 or ISO-9141.

Abstract: A communication control apparatus, provided with an echo back comparison detecting unit (30) detecting something abnormal of communication data from itself or an abnormal state generated at a data line (4), by starting transmission of communication data from itself following a detection of a line state detecting unit (29), when the line state detecting unit (29) detects that transmission of communication data from another communication apparatus to a data line (4) is started in a transmission permissible section, and by taking in communication data at the data line (4) and by comparing it with communication data having been transmitted from itself, and further provided with a transmission mark generating unit (23) shortening a bit width of data indicating a start of communication data transmitted from itself, prevents an abnormal waveform from being transmitted to the data line (4) because accuracy of echo back comparison is improved and delay tolerance of the data line (4) is eased.

Abstract: The evenness of the brightness of a display apparatus is enhanced. A drive control signal generation circuit supplies drive control signals to drive circuits, respectively. Drive power source input pads are connected to each other by a drive power source line in a chip, and provided with potentials from the same power source outside the chip. The drive circuits respectively comprise drive circuit input terminals which are connected at predetermined intervals to the drive power source line. Under the control of the drive control signals, the drive circuits transmit potentials received at the drive circuit input terminals to drive signal output pads, respectively. A difference in drive output impedance between the drive signal output pads is thereby suppressed.

Abstract: A communication control apparatus is constituted such that, when functioning as a receiving side, an IFR 20 is replied only when receiving normally or only when not receiving normally, also at the time of multiple address communication, when functioning as the receiving side, the IFR 20 is replied only when receiving normally or only when not receiving normally, and furthermore, at the time of multiple address communication, a reply data row is replied only when an IFR control code 57 sent from a transmitting side is larger than respective source addresses, or only when smaller. It is possible to find out occurrence of errors in a unit on the transmitting side, by one frame communication, and accuracy of the multiple address communication is improved, besides the source address of the unit having an unspecific source address can be retrieved easily in one specific unit.

Abstract: A Data transmission device controlled by a processor which has a transmission control apparatus (14) which re-transmits transmission data which was previously set by a microcomputer (10) and which was unable to be transmitted in a first transmission attempt. The transmission control apparatus (14) has a transmit data word number comparing circuit (28) which determines whether a value of a set transmit data word number is within the limits prescribed by a communication standard. In the event of a failed transmission attempt, the microcomputer sets a transmit data word number greater than the number prescribed by the communication standard.