Texas Instruments TMS320DM643x manual Bandwidth Manager

Models: TMS320DM643x

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2.4.3 Bandwidth Manager

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Internal Peripherals

2.4.3 Bandwidth Manager

The bandwidth manager provides a programmable interface for optimizing bandwidth among the requesters for resources, which include the following:

EDMA-initiated DMA transfers (and resulting coherency operations)

IDMA-initiated transfers (and resulting coherency operations)

Programmable cache coherency operations

Block based coherency operations

Global coherency operations

CPU direct-initiated transfers

Data access (load/store)

Program access

The resources include the following:

L1P memory

L1D memory

L2 memory

Resources outside of C64x+ Megamodule: external memory, on-chip peripherals, registers

Since any given requestor could potentially block a resource for extended periods of time, the bandwidth manager is implemented to assure fairness for all requesters.

The bandwidth manager implements a weighted-priority-driven bandwidth allocation. Each requestor (EDMA, IDMA, CPU, etc.) is assigned a priority level on a per-transfer basis. The programmable priority level has a single meaning throughout the system. There are a total of nine priority levels, where priority zero is the highest priority and priority eight is the lowest priority. When requests for a single resource contend, access is granted to the highest-priority requestor. When the contention occurs for multiple successive cycles, a contention counter assures that the lower-priority requestor gets access to the resource every 1 out of n arbitration cycles, where n is programmable. A priority level of -1 represents a transfer whose priority has been increased due to expiration of the contention counter or a transfer that is fixed as the highest-priority transfer to a given resource.

SPRU978E–March 2008

TMS320C64x+ Megamodule

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Texas Instruments TMS320DM643x manual Bandwidth Manager