Modes Of Operation - NXP Semiconductors freescale KV4 Series Reference Manual

Modes of operation

• 16-channel implementation that performs complex data transfers with minimal
intervention from a host processor
• Internal data buffer, used as temporary storage to support 16- and 32-byte
transfers
• Connections to the crossbar switch for bus mastering the data movement
• Transfer control descriptor (TCD) organized to support two-deep, nested transfer
operations
• 32-byte TCD stored in local memory for each channel
• An inner data transfer loop defined by a minor byte transfer count
• An outer data transfer loop defined by a major iteration count
• Channel activation via one of three methods:
• Explicit software initiation
• Initiation via a channel-to-channel linking mechanism for continuous transfers
• Peripheral-paced hardware requests, one per channel
• Fixed-priority and round-robin channel arbitration
• Channel completion reported via optional interrupt requests
• One interrupt per channel, optionally asserted at completion of major iteration
count
• Optional error terminations per channel and logically summed together to form
one error interrupt to the interrupt controller
• Optional support for scatter/gather DMA processing
• Support for complex data structures
In the discussion of this module, n is used to reference the channel number.
23.2 Modes of operation
The eDMA operates in the following modes:
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KV4x Reference Manual, Rev. 2, 02/2015
Preliminary
Freescale Semiconductor, Inc.