| abstract |
A data processing system with improved data transfer capabilities. All units in the system, including a random access memory unit, are connected in parallel. Data is transferred between any two units asynchronously with respect to a processor unit which normally controls the system. Other units can obtain system control by making a request which is honored if it has sufficient priority. Transfers requiring processor unit operation are made after an instruction is processed and may divert the processor unit to an interruption routine. Other transfers can be made whenever another unit in the system is not making a transfer. System control is returned to the processor unit or another peripheral unit when the data transfer is completed. If an interruption routine is to be executed, control is returned to the processor directly. Data transfers are controlled by synchronization signals from the controlling peripheral unit and the other unit involved in the transfer. |