Method and arrangement for controlling the coupling between two digital processor systems which are jointly or separately clocked

摘要

When controlling the coupling between two digital processor systems, which are jointly or separately clocked, via a common main memory unit, interrupts of the processor with a higher priority occur even if the latter wants to access non-common memory areas in the case of a fixed priority allocation. This is disturbing. According to the invention, an access control is provided which only allows unrestricted access to the processor system which really accesses first in time and then recognises the processor system which has hitherto been waiting after the access of the thus prioritised processor system has ended. After completion of the accesses, a priority allocation of the processor system which has accessed last remains stored. This last priority allocation changes to a random priority allocation after each new switching-on of the arrangement, this storage of the last priority allocation or setting of the random priority allocation being used for solving conflicts in the case of an absolutely simultaneous access by both processor systems. The priority allocation used mandatorily changes after the conflict has been resolved. <IMAGE>