Abstract: An interface control circuit includes a shift register which is parallel loaded with a 17 bit binary code and with control information comprising two bits of opposite level loaded in the head cells of the register, the first bit having a control function, the second having a separation function from the 17 bit binary code. The parallel loading is performed by a load command which also sets a control flip flop and wherein a timing circuit, triggered by command, controls in continuous mode the interlocked interface dialogue as long as the control flip flop is set, and causes the register to shift its contents so as to serially unload the binary code to the interface and to serially load the register with the logic level of the control bit, until, at the completion of transferring the control bit level present at a predetermined number of register outputs is inverted, reintroduced in the first register cell and causes the control flip flop to reset and the dialogue to halt.

Abstract: Arbitration circuit operates for common bus access granting where the asynchronous access requests are latched in a register by the rising edge of a periodical square wave timing signal, and from there transferred to a logical priority network, implemented with a programmable logic array.