Patent ID: 6587932
Filing Date: 2003-07-01
Classification: G06F

Abstract:
A system for controlling shared access to a memory, said system comprising:a memory connected to a data bus and an address bus; a plurality of peripheral devices divided into a priority peripheral device and auxiliary peripheral devices, each peripheral being clocked by its own internal clock signal and being able to generate a memory access request signal; a sequencer that is regulated by the internal clock signal of the priority peripheral device so as to formulate a repetitive time frame; and a control circuit that is coupled to the peripheral devices, wherein the time frame is subdivided into a plurality of groups of time windows, each group of time windows is allocated to one of the peripheral devices, when a memory access request signal is generated by one of the peripheral devices, the control circuit delivers an enabling signal to that one peripheral device only during a time window within the group of time windows allocated to the one peripheral device so as to only allow the one peripheral device to access the memory during time windows allocated to that one peripheral device, each of the peripheral devices comprises: an input/output circuit that is connected to the data bus and the address bus; storage means for storing data extracted from the memory or to be written to the memory; and a control port that receives the enabling signal for the data stored in the input/output circuit, one of the auxiliary peripheral devices includes a central processing unit, and when a memory access request signal is generated by the central processing unit during a time window within one of the groups of time windows not allocated to the auxiliary peripheral device that includes the central processing unit, an inhibiting circuit within the control circuit disables the internal operation of the central processing unit until the control circuit delivers an enabling signal to the auxiliary peripheral device that includes the central processing unit.