Arbitration Mode Considerations; Fixed Channel Arbitration; Round-Robin Channel Arbitration; Performing Dma Transfers - NXP Semiconductors freescale KV4 Series Reference Manual

Table of Contents

Initialization/application information

For all error types other than channel priority error, the channel number causing the error

is recorded in the Error Status register (DMAx_ES). If the error source is not removed

before the next activation of the problem channel, the error is detected and recorded

If priority levels are not unique, when any channel requests service, a channel priority

error is reported. The highest channel priority with an active request is selected, but the

lowest numbered channel with that priority is selected by arbitration and executed by the

eDMA engine. The hardware service request handshake signals, error interrupts, and

error reporting is associated with the selected channel.

23.5.3 Arbitration mode considerations

This section discusses arbitration considerations for the eDMA.

In this mode, the channel service request from the highest priority channel is selected to

Channels are serviced starting with the highest channel number and rotating through to

the lowest channel number without regard to the channel priority levels.

This section presents examples on how to perform DMA transfers with the eDMA.

To perform a simple transfer of n bytes of data with one activation, set the major loop to

one (TCDn_CITER = TCDn_BITER = 1). The data transfer begins after the channel

service request is acknowledged and the channel is selected to execute. After the transfer

is complete, the TCDn_CSR[DONE] bit is set and an interrupt generates if properly

KV4x Reference Manual, Rev. 2, 02/2015

Freescale Semiconductor, Inc.