Data transmission system

Claim 2

A central control unit in a data transmission system for an automobile, comprising: a data processing unit; at least one local control unit connected to one or more input/output devices of the automobile; and a communication control unit connected to said data processing unit and including means for performing data transmission in a half duplex mode on a transmission medium with said local control unit; said communication control unit having first means for receiving a frame of data from said local control unit via said transmission medium and for counting the data as it is received, second means connected to said first means for detecting an error in the received frame of data and for outputting a data process requesting signal only when reception the count of received data indicates that of a full frame of data has been completed and there is no error in the received data, and third means for applying an interruption request signal to said data processing unit in response to said data process requesting signal being outputted by said second means, wherein said communication control unit includes means for cancelling an operation for receiving a frame of data when an error is detected in the frame of data by said error detecting means so that said communication control unit is made ready for receiving another frame of data; and said data processing unit including means for processing received data in response to the interrupt request signal from said communication control unit.

Claim 3

A central control unit according to claim 1, where said second means in said communication control unit includes first storing means for storing said data process requesting signals; and further comprising masking means connected to said third means for masking said interruption request signal in response to a command from said data processing unit, including second storing means of storing information indicating that said data processing unit is not ready for processing received data and for outputting a mask signal when said information is stored therein, and said second means further includes means for outputting said interruption requesting signal in response to the storing of said data process requesting signal in said first storing means and in the absence of the outputting of said mask signal from said second storing means.

Claim 4

A central control unit according to claim 1, wherein the local control unit transmits a frame of data and data which is the inverse of said frame of data, and said error detecting means detects an error in the received frame of data by comparing the data and the inverse data which said data communication unit has received.

Claim 5

A central control unit in a data transmission system for an automobile, comprising: a data processing unit; at least one local control unit connected to one or more input/output devices of the automobile; and a communication control unit connected to said data processing unit and including means for performing data transmission in a half duplex mode on a transmission medium with said local control unit; said communication control unit having first means for receiving a frame of data from said local control unit via said transmission medium, second means connected to said first means for detecting an error in the received frame of data and for outputting a data process requesting signal only when reception of a frame of data has been completed and there is no error in the received data, and third means for applying an interruption request signal to said data processing unit when said data process requesting signal has been outputted by said second means, wherein said communication control unit includes means for cancelling an operation for receiving a frame of data when an error is detected in the frame of data by said error detecting means so that said communication control unit is made ready for receiving another frame of data; and said data processing unit including means for processing received data in response tot he interrupt request signal from said communication control unit; wherein the local control unit transmits a frame of data and data which is the inverse of said frame of data, and said error detecting means detects an error in the received frame of data by comparing the data and the inverse data which said data communication unit has received; wherein said communication control unit includes a shift register for storing a frame of data received from said local control unit, and said error detecting means includes an EXCLUSIVE OR gate having inputs connected to the first and last stages of said shift register and an error detector responsive to the output of said EXCLUSIVE OR gate for producing an output stages of said shift register and an error detector responsive to the output of said EXCLUSIVE OR gate for producing an output signal indicating detected non-coincidence between corresponding bits of said frame of data and said inverse frame of data.

Claim 6

A central control unit in a data transmission system for an automobile, comprising: a data processing unit; at least one local control unit connected to one or more input/output devices of the automobile; and a communication control unit connected to said data processing unit and including means for performing data transmission in a half duplex mode on a transmission medium with said local control unit; said communication control unit having first means for receiving a frame of data from said local control unit via said transmission medium, second means connected to said first means for detecting an error in the received frame of data and for outputting a data process requesting signal only when reception of a frame of data has been completed and there is no error in the received data, and third means for applying an interruption request signal to said data processing unit when said data process requesting signal has been outputted by said second means, wherein said communication control unit includes means for cancelling an operation for receiving a frame of data when an error is detected in the frame of data by said error detecting means so that said communication control unit is made ready for receiving another frame of data; and said data processing unit including means for processing received data in response tot he interrupt request signal from said communication control unit; wherein the local control unit transmits a frame of data and data which is the inverse of said frame of data, and said error detecting means detects an error in the received frame of data by comparing the data and the inverse data which said data communication unit has received; wherein said communication control unit includes a shift register for storing a frame of data received from said local control unit, and said error detecting means includes an EXCLUSIVE OR gate having inputs connected to the first and last stages of said shift register and an error detector responsive to the output of said EXCLUSIVE OR gate for producing an output stages of said shift register and an error detector responsive to the output of said EXCLUSIVE OR gate for producing an output signal indicating detected non-coincidence between corresponding bits of said frame of data and said inverse frame of data.

Claim 7

A central control unit according to claim 4, wherein said communication control unit further includes a sequence control signal generator for generating sequence control signals to control operations in said communication control unit in a predetermined sequence, and means for resetting said sequence control signal generator in response to the output signal of said error detector to initiate a new sequence of operations in connection with another frame of data.

Claim 8

A data transmission system for an automobile, comprising: a central processing unit for sending control data for controlling the automobile through a communication processing unit; at least one terminal processing unit for receiving said control data from said central processing unit through said communication processing unit; and transmission means for connecting said central processing unit with said terminal processing unit to permit information transmission therebetween; said communication processing unit including a first counter for sending control data received from said central processing unit to a terminal processing unit on the basis of a count value of said first counter, and after sending said control data, receiving a signal from said terminal processing unit on the basis of the count value of said first counter and generating an interrupt request signal when the count value of said first counter reaches a predetermined value.

Claim 9

A data transmission system for an automobile, comprising: a central processing unit for sending control data for controlling the automobile through a communication processing unit; at least one terminal processing unit for receiving said control data from said central processing unit through said communication processing unit; and transmission means for connecting said central processing unit with said terminal processing unit to permit information transmission therebetween; said communication processing unit including a first counter for sending control data received from said central processing unit to a terminal processing unit on the basis of a count value of said first counter, and after sending said control data, receiving a signal from said terminal processing unit on the basis of the count value of said first counter and generating an interrupt request signal when the count value of said first counter reaches a predetermined value.

Claim 10

A data transmission system according to claim 6, wherein said communication processing means includes error detecting means for inhibiting generation of said interrupt request signal when said detecting means detects errors in received data.

Claim 11

A data transmission system according to claim 6, wherein said terminal processing unit includes a second counter operating in synchronization with said first counter, reception of said control data being performed on the basis of a count value of said second counter, a signal being received from detection means on the basis of said control data, and further the signal or predetermined data from the detection means being transmitted to said communication processing unit.