
Enhanced Direct Memory Access (eDMA)
16-2
Freescale Semiconductor
16.3
Features
The eDMA is a highly-programmable data-transfer engine optimized to minimize the required
intervention from the host processor. It is intended for use in applications where the data size to be
transferred is statically known and not defined within the data packet itself. The eDMA module features:
•
All data movement via dual-address transfers: read from source, write to destination
— Programmable source and destination addresses and transfer size, plus support for enhanced
addressing modes
•
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-byte burst 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 continual transfers
— Peripheral-paced hardware requests (one per channel)
•
Support for 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
— Error terminations are optionally enabled per channel and logically summed together to form
one error interrupt to the interrupt controller
•
Optional support for scatter/gather DMA processing
Throughout this chapter,
n
is used to reference the channel number.
16.4
Modes of Operation
16.4.1
Normal Mode
In normal mode, the eDMA transfers data between a source and a destination. The source and destination
can be a memory block or an I/O block capable of operation with the eDMA.
A service request initiates a transfer of a specific number of bytes (NBYTES) as specified in the transfer
control descriptor (TCD). The minor loop is the sequence of read-write operations that transfers these
NBYTES per service request. A major loop is the number of minor loop iterations defining a task.
MCF5329 Reference Manual, Rev 3
Содержание MCF5329
Страница 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 126: ...Enhanced Multiply Accumulate Unit EMAC 4 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 564: ...Liquid Crystal Display Controller LCDC 22 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 692: ...Programmable Interrupt Timers PIT0 PIT3 28 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 720: ...Queued Serial Peripheral Interface QSPI 30 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 790: ...Message Digest Hardware Accelerator MDHA 33 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 902: ...Register Memory Map Quick Reference A 26 Freescale Semiconductor MCF5329 Reference Manual Rev 3...