Information transfer method and arrangement

In an arrangement comprising a first terminal for transmitting data frames on a bus, said first terminal comprising a control unit, a co-processor, and a memory comprising a transmit buffer area and a data and control area wherein said control unit initiates the transmission of data by loading data into said transmit buffer area and setting said co-processor to transmit first data frames on said bus, said first data frames including data loaded into said transmit buffer area by said control unit, the method comprising:

• determining the actual locations in said data and control area of said memory storing data to be transmitted on said bus;
• setting said co-processor to transmit on said bus a second data frame including the data stored in said actual locations of said data and control area determined in the determining step;
• transmitting by said co-processor said second data frame comprising the data in said actual locations of said data and control area;
• and
• resetting said co-processor to transmit first data frames including data from said transmit buffer area.

In an arrangement comprising at least three terminals connected to a bus for transmitting and receiving frames of data, a first of said terminals comprising a control unit, a co-processor, and a memory comprising a receive buffer area and a data and control area wherein the co-processor receives frames of data from said bus and stores the frames of data so received in said receive buffer area and said control unit reads received data from said receive buffer area for use by said control unit, the method of transmitting a frame of data from a second of said terminals to said first terminal comprising:

• isolating said first terminal from receiving frames of data from any of said terminals except said second terminal;
• setting said co-processor to store received frames of data in particular locations in the data and control area of said memory, said particular locations being the actual locations where the data is to be stored;
• transmitting by said second terminal a frame of data to said first terminal via said bus;
• storing said frame of data in said particular locations;
• and
• resetting said co-processor to store subsequent frames of data in said receive buffer area of said memory.

In an arrangement comprising a first terminal comprising a first control unit, a first co-processor, and a first memory comprising a data and control area and a receive buffer area identified by a first pointer;

• a second terminal comprising a second control unit, a second co-processor, and a second memory comprising a data and control area and a transmit buffer area identified by a second pointer;
• and a communication bus connecting said first and said second terminals wherein said transmit buffer area stores information to be transmitted on said communication bus and said receive buffer area stores information received from said communication bus, the method comprising:
• changing said second pointer to a third pointer identifying storage locations in the data and control area of said second memory, which storage locations contain data to be transmitted to said first terminal;
• changing said first pointer to a fourth pointer identifying storage locations in the data and control area of said first memory where data is to be stored;
• transmitting by said second co-processor the data stored in the locations identified by said third pointer on said bus;
• and
• storing by said first co-processor in the locations identified by said fourth pointer data transmitted on said bus.