A memory controller for controlling accesses to a memory storing display entities including network application data displayed on a display screen of a television system. For performing a display screen refresh operation, the network application data is retrieved with a predetermined period. Accordingly, the memory controller determines an expected time for receiving the next request for retrieving the network application data for screen refresh. The memory controller blocks any lower priority memory access requests from a few clock cycles prior to the determined expected time. As a result, the requests for retrieving network application data can be serviced in an acceptable time.