
Enhanced Direct Memory Access Controller (eDMA)
MPC5644A Microcontroller Reference Manual, Rev. 6
150
Freescale Semiconductor
conditions except scatter-gather and minor loop link error are reported as the channel is activated and
assert an error interrupt request if enabled. When properly enabled, a scatter-gather configuration error is
reported when the scatter-gather operation begins at major loop completion. 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 immediately stopped and the
appropriate bus error flag is set. In this case, the state of the channel’s transfer control descriptor is updated
by the DMA engine with the current source address, destination address, and minor loop byte count at the
point of the fault. If a bus error occurs on the last read prior to beginning the write sequence, the write is
executed using the data captured during the bus error. If a bus error occurs on the last write prior to
switching to the next read sequence, the read sequence is executed before the channel is terminated due to
the destination bus error.
A transfer may be cancelled by software via the bit EDMA_CR[CX]. When a cancel transfer request is
recognized, the eDMA engine stops processing the channel. The current read-write sequence is allowed to
finish. If the cancel occurs on the last read-write sequence of a major or minor loop, the cancel request is
discarded and the channel retires normally.
The error cancel transfer is the same as a cancel transfer except the DMAES register is updated with the
cancelled channel number and error cancel bit is set. The TCD of a cancelled channel has the source
address and destination address of the last transfer saved in the TCD. It is the responsibility of the user to
initialize the TCD again should the channel need to be restarted because the aforementioned fields have
been modified by the eDMA engine and no longer represent the original parameters. When a transfer is
cancelled via the error cancel transfer mechanism (setting EDMA_CR[ECX]), the channel number is
loaded into field EDMA_ESR[ERRCHN] and the bits EDMA_ESR[ECX] and EDMA_ESR[VLD] are
set. In addition, an error interrupt may be generated if enabled. Refer to
Registers (EDMA_ERH, EDMA_ERL)
.
The occurrence of any type of error causes the DMA engine to stop the active channel and the appropriate
channel bit in the eDMA error register to be asserted. At the same time, the details of the error condition
are loaded into the EDMA_ESR. The major loop complete indicators, setting the transfer control
descriptor DONE flag and the possible assertion of an interrupt request, are not
affected when an error is
detected. After the error status has been updated, the DMA engine continues to operate by servicing the
next appropriate channel. A channel that experiences an error condition is not automatically disabled. If a
channel is terminated by an error and then issues another service request before the error is fixed, that
channel will execute and terminate with the same error condition.
Содержание MPC5644A
Страница 2: ...MPC5644A Microcontroller Reference Manual Rev 6 2 Freescale Semiconductor...
Страница 24: ...MPC5644A Microcontroller Reference Manual Rev 6 24 Freescale Semiconductor...
Страница 26: ...MPC5644A Microcontroller Reference Manual Rev 6 26 Freescale Semiconductor...
Страница 52: ...Introduction MPC5644A Microcontroller Reference Manual Rev 6 52 Freescale Semiconductor...
Страница 56: ...Memory Map MPC5644A Microcontroller Reference Manual Rev 6 56 Freescale Semiconductor...
Страница 130: ...Device Performance Optimization MPC5644A Microcontroller Reference Manual Rev 6 130 Freescale Semiconductor...
Страница 204: ...Multi Layer AHB Crossbar Switch XBAR MPC5644A Microcontroller Reference Manual Rev 6 204 Freescale Semiconductor...
Страница 212: ...Peripheral Bridge PBRIDGE MPC5644A Microcontroller Reference Manual Rev 6 212 Freescale Semiconductor...
Страница 558: ...System Integration Unit SIU MPC5644A Microcontroller Reference Manual Rev 6 558 Freescale Semiconductor...
Страница 582: ...Frequency modulated phase locked loop FMPLL MPC5644A Microcontroller Reference Manual Rev 6 582 Freescale Semiconductor...
Страница 766: ...Enhanced Time Processing Unit eTPU2 MPC5644A Microcontroller Reference Manual Rev 6 766 Freescale Semiconductor...
Страница 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
Страница 1236: ...System Information Module and Trim SIM MPC5644A Microcontroller Reference Manual Rev 6 1236 Freescale Semiconductor...
Страница 1250: ...Cyclic Redundancy Checker CRC Unit MPC5644A Microcontroller Reference Manual Rev 6 1250 Freescale Semiconductor...
Страница 1336: ...Deserial Serial Peripheral Interface DSPI MPC5644A Microcontroller Reference Manual Rev 6 1336 Freescale Semiconductor...
Страница 1388: ...Enhanced Serial Communication Interface ESCI MPC5644A Microcontroller Reference Manual Rev 6 1388 Freescale Semiconductor...
Страница 1440: ...FlexCAN Module MPC5644A Microcontroller Reference Manual Rev 6 1440 Freescale Semiconductor...
Страница 1624: ...FlexRay Communication Controller FlexRay MPC5644A Microcontroller Reference Manual Rev 6 1624 Freescale Semiconductor...
Страница 1670: ...JTAG Controller JTAGC MPC5644A Microcontroller Reference Manual Rev 6 1670 Freescale Semiconductor...
Страница 1692: ...Nexus Port Controller NPC MPC5644A Microcontroller Reference Manual Rev 6 1692 Freescale Semiconductor...
Страница 1701: ...Development Trigger Semaphore DTS MPC5644A Microcontroller Reference Manual Rev 6 Freescale Semiconductor 1701...
Страница 1702: ...Development Trigger Semaphore DTS MPC5644A Microcontroller Reference Manual Rev 6 1702 Freescale Semiconductor...