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Enhanced Direct Memory Access Controller (eDMA)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor
177
transfer control parameter shown in
, for the selected channel into its internal address path
module. As the TCD is being read, the first transfer is initiated on the system bus unless a configuration
error is detected. Transfers from the source (as defined by the source address, EDMA_TCD[SADDR]) to
the destination (as defined by the destination address, EDMA_TCD.DADDR) continue until the specified
number of bytes (EDMA_TCD[NBYTES]) have been transferred. When the transfer is complete, the
DMA engine's local EDMA_TCD[SADDR], EDMA_TCD.DADDR, and EDMA_TCD.CITER are
written back to the main TCD memory and any minor loop channel linking is performed, if enabled. If the
major loop is exhausted, further post processing is executed; for example, interrupts, major loop channel
linking, and scatter-gather operations, if enabled.
shows how each DMA request initiates one minor loop transfer (iteration) without CPU
intervention. DMA arbitration can occur after each minor loop, and one level of minor loop DMA
pre-emption is allowed. The number of minor loops in a major loop is specified by the beginning iteration
count (biter).
Table 8-21. TCD primary control and status fields
TCD field name
Description
START
Control bit to start channel when using a software initiated DMA service
(Automatically cleared by hardware)
ACTIVE
Status bit indicating the channel is currently in execution
DONE
Status bit indicating major loop completion (cleared by software when using a
software initiated DMA service)
D_REQ
Control bit to disable DMA request at end of major loop completion when using
a hardware-initiated DMA service
BWC
Control bits for throttling bandwidth control of a channel
E_SG
Control bit to enable scatter-gather feature
INT_HALF
Control bit to enable interrupt when major loop is half complete
INT_MAJ
Control bit to enable interrupt when major loop completes
Содержание MPC5644A
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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...
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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...
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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...