System for the asynchronous transporting of data between active functional units

A device comprising:

• at least a first and a second active functional unit;
• said functional units interconnected by a data bus line having a plurality of parallel single-bit data lines, and by a first single-bit control line for communicating request signal transitions produced by a first transition generator from the first active functional unit to the second active functional unit, and by a second single-bit control line for communicating acknowledge signal transitions produced by a second transition generator from the second active functional unit to the first active funcional unit;
• each functional unit being connected to each single-bit data line both via one data receiver and via one output circuit per single-bit data line, said output circuit having at least:
• one first state for imposing a respective first data value at a low impedance on the data bit line connected thereto and having furthermore one second state for forming a second data value at a high impedance on the data bit line connected thereto;
• wherein furthermore said first active functional unit has first cycling means for supplying in a first operational mode a plurality of data bits on said data bus before generation of a request signal transition and upon reception of a subsequent acknowledge signal transition driving the output circuits of the first active functional unit exclusively to their second states for enabling the data receivers of the first active functional unit;
• and wherein furthermore said second active functional unit has second cycling means for supplying in a second operational mode a plurality of data bits on said data bus before generation of an acknowledge signal transition and upon reception of a subsequent request signal transition driving the output circuits of the second active functional unit exclusively to their second states for enabling the data receivers of the second active functional units.