Abstract: Command reordering in the hub-interface unit (HIU) of Enhanced Direct Memory Access (EDMA) functions is described. Without command reordering in the EDMA, commands are issued by the HIU to the peripheral in order of issue. If the higher priority transfers are issued later by the EDMA, the previously issued lower priority transfers would block the higher priority transfers. Command reordering in the HIU causes transfers to be reordered and issued to the peripheral based on their priority. Reordering allows the EDMA and HIU is to give due service to high priority transfer requests with decreased weight placed on the order in which the requests were issued.

Abstract: A data transfer apparatus with hub and ports includes design configurable hub interface units (HIU) between the ports and corresponding external application units. The configurable HIU provides a single generic superset HIU that can be configured for specific more specialized applications during implementation as part of design synthesis. Configuration allows the super-set configurable HIU to be crafted into any one of several possible special purpose HIUs. This configuration is performed during the design phase and is not applied in field applications. Optimization aimed at eliminating functional blocks not needed in a specific design and simplifying and modifying other functional blocks allows for the efficient configuring of these other types of HIUs. Configuration of HIUs for specific needs can result in significant savings in silicon area and in power consumption.