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Enhanced Direct Memory Access (eDMA)
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor
9-3
•
Transfer control descriptor (TCD) organized to support two-deep, nested transfer operations
— 32-byte TCD per channel stored in local memory
— 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)
NOTE
For all three methods, one activation per execution of the minor loop is
required.
•
Support for fixed-priority and round-robin channel arbitration
•
Support for complex data structures
•
Support to cancel transfers via software
•
Channel completion reported via optional interrupt requests
— One interrupt per channel, optionally asserted at completion of major iteration count
— Error terminations are enabled per channel, and logically summed together to form two error
interrupts
•
Support for scatter/gather DMA processing
•
Any channel can be programmed so that it can be suspended by a higher priority channel’s
activation, before completion of a minor loop
Throughout this chapter,
n
is used to reference the channel number. Additionally, data sizes are defined as
byte (8-bit), halfword (16-bit), word (32-bit) and doubleword (64-bit).
9.1.2
Modes of Operation
9.1.2.1
Normal Mode
In normal mode, the eDMA is used to transfer 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.
9.1.2.2
Debug Mode
If enabled by EDMA_CR[EDBG] and the CPU enters debug mode, the eDMA does not grant a service
request when the debug input signal is asserted. If the signal asserts during a data block transfer as
described by a minor loop in the current active channel’s TCD, the eDMA continues the operation until
the minor loop completes.
Summary of Contents for MPC5566
Page 81: ...Introduction MPC5566 Microcontroller Reference Manual Rev 2 1 24 Freescale Semiconductor...
Page 135: ...Signal Description MPC5566 Microcontroller Reference Manual Rev 2 2 54 Freescale Semiconductor...
Page 189: ...Reset MPC5566 Microcontroller Reference Manual Rev 2 4 20 Freescale Semiconductor...
Page 603: ...Flash Memory MPC5566 Microcontroller Reference Manual Rev 2 13 38 Freescale Semiconductor...
Page 609: ...SRAM MPC5566 Microcontroller Reference Manual Rev 2 14 6 Freescale Semiconductor...
Page 1073: ...MPC5566 Microcontroller Reference Manual Rev 2 22 36 Freescale Semiconductor...
Page 1185: ...Nexus MPC5566 Microcontroller Reference Manual Rev 2 25 92 Freescale Semiconductor...