Apparatus and method for providing round-robin arbitration

Apparatus for providing round-robin arbitration between requests for access to a shared resource, such as a data bus (7), shared by a plurality of hardware modules, said apparatus comprising a central counter (1) cyclically driven between multiple count states by a clock C, each count state being associated with a request for access to the shared resource (7) by one of the plurality of hardware modules, characterized by comprising

• a count state bus (3) connecting the central counter (1) to each of the hardware modules for providing the count state to the hardware modules,
• each hardware module comprising a comparator (4) for comparing the count state on the count state bus (3) with the count state associated with the hardware module, the output from said comparator (4) being used to enable
• i) the transmission of an external request signal R to the central counter (1) and
• ii) the transmission of an internal grant signal Gi to the hardware module,
• whenever the hardware module has a request Ri for access to the shared resource, the external request signal R to the central counter (1) being used to disable (2) the clock signal C to the counter (1) and
• the internal grant signal Gi being used to grant access from the hardware module to the shared resource (7) until the internal request signal Ri is deactivated by the hardware module when terminating its access to the shared resource (7), thereby deactivating the external request signal R and enabling the clock signal C to the counter (1), whereby the counter resumes cyclically counting between the multiple count states.