Abstract: A method is disclosed for achieving synchronization in an array of semi-synchronous devices. A processor array has an array of processor elements, wherein each of said processor elements comprises a cycle counter, and a master processor element is able to transmit control command signals to each of the other processor elements. Each processor element is such that, on receipt of a control command signal, it acts on that signal only when its cycle counter reaches a predetermined value, and the master processor element is such that it transmits control command signals only when its cycle counter takes a value which is within a predetermined range, or “safe window”. By appropriate setting of the “safe window”, it can be guaranteed that, when the master processor element transmits a control command signal to each of the other processor elements, those command control signals are acted upon at corresponding times within the other processor elements.

Abstract: There is disclosed a processor array, which achieves an approximately constant latency. Communications to and from the farthest array elements are suitably pipelined for the distance, while communications to and from closer array elements are deliberately “over-pipelined” such that the latency to all end-point elements is the same number of clock cycles. The processor array has a plurality of primary buses, each connected to a primary bus driver, and each having a respective plurality of primary bus nodes thereon; respective pluralities of secondary buses, connected to said primary bus nodes; a plurality of processor elements, each connected to one of the secondary buses; and delay elements associated with the primary bus nodes, for delaying communications with processor elements connected to different ones of the secondary buses by different amounts, in order to achieve a degree of synchronization between operation of said processor elements.