NXP Semiconductors freescale KV4 Series, Reference Manual

Page: 429 / 1359

• All source reads and destination writes must be configured to the natural boundary of
the programmed transfer size respectively.
• In fixed arbitration mode, a configuration error is caused by any two channel
priorities being equal. All channel priority levels must be unique when fixed
arbitration mode is enabled.
NOTE
When two channels have the same priority, a channel
priority error exists and will be reported in the Error Status
register. However, the channel number will not be reported
in the Error Status register. When all of the channel
priorities within a group are not unique, the channel
number selected by arbitration in undetermined.
To aid in Channel Priority Error (CPE) debug, set the Halt
On Error bit in the DMA’s Control Register. If all of the
channel priorities within a group are not unique, the DMA
will be halted after the CPE error is recorded. The DMA
will remain halted and will not process any channel service
requests. Once all of the channel priorities are set to unique
numbers, the DMA may be enabled again by clearing the
Halt bit.
• If a scatter/gather operation is enabled upon channel completion, a configuration
error is reported if the scatter/gather address (DLAST_SGA) is not aligned on a 32-
byte boundary.
• If minor loop channel linking is enabled upon channel completion, a configuration
error is reported when the link is attempted if the TCDn_CITER[E_LINK] bit does
not equal the TCDn_BITER[E_LINK] bit.
If enabled, all configuration error conditions, except the scatter/gather and minor-loop
link errors, report as the channel activates and asserts an error interrupt request. A scatter/
gather configuration error is reported when the scatter/gather operation begins at major
loop completion when properly enabled. A minor loop channel link configuration error is
reported when the link operation is serviced at minor loop completion.
If a system bus read or write is terminated with an error, the data transfer is stopped and
the appropriate bus error flag set. In this case, the state of the channel's transfer control
descriptor is updated by the eDMA engine with the current source address, destination
address, and current iteration count at the point of the fault. When a system bus error
occurs, the channel terminates after the next transfer. Due to pipeline effect, the next
transfer is already in progress when the bus error is received by the eDMA. If a bus error
Chapter 23 Direct Memory Access Controller (eDMA)
KV4x Reference Manual, Rev. 2, 02/2015
Freescale Semiconductor, Inc.
Preliminary
429