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DMA Channel Multiplexer (DMA_MUX)
PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor
23-11
Figure 23-6. DMA_MUX Channel 8–31 Block Diagram
23.4.3
Always Enabled DMA Sources
In addition to the 55 peripherals that can be used as DMA sources, there are four additional DMA sources
that are always enabled. Unlike the peripheral DMA sources, where the peripheral controls the flow of data
during DMA transfers, the always enabled sources provide no such throttling of the data transfers. These
sources are most useful in the following cases:
•
Doing DMA transfers to/from GPIO—Moving data from/to one or more GPIO pins, either
un-throttled (i.e.,as fast as possible), or periodically (using the DMA triggering capability).
•
Doing DMA transfers from memory to memory—Moving data from memory to memory, typically
as fast as possible, sometimes with software activation.
•
Doing DMA transfers from memory to the external bus (or vice-versa)—Similar to memory to
memory transfers, this is typically done as quickly as possible.
•
Any DMA transfer that requires software activation—Any DMA transfer that should be explicitly
started by software.
In cases where software should initiate the start of a DMA transfer, an always enabled DMA source can
be used to provide maximum flexibility. When activating a DMA channel via software, subsequent
Peripheral Source #1
Peripheral Source #2
Peripheral Source #3
Peripheral Source #55
DMA Channel #n
Always Disabled
Always Enabled
CHCONFIGn[SOURCE]
Source #60
Always Enabled
Source #63
n = 8 to 31
Source #0
Summary of Contents for PXN2020
Page 1: ...PXN20 Microcontroller Reference Manual Devices Supported PXN2020 PXN2120 PXN20RM Rev 1 06 2011...
Page 42: ...PXN20 Microcontroller Reference Manual Rev 1 lxiv Freescale Semiconductor...
Page 64: ...Introduction PXN20 Microcontroller Reference Manual Rev 1 1 22 Freescale Semiconductor...
Page 112: ...Signal Description PXN20 Microcontroller Reference Manual Rev 1 3 44 Freescale Semiconductor...
Page 118: ...Resets PXN20 Microcontroller Reference Manual Rev 1 4 6 Freescale Semiconductor...
Page 372: ...e200z6 Core Z6 PXN20 Microcontroller Reference Manual Rev 1 13 8 Freescale Semiconductor...
Page 412: ...e200z0 Core Z0 PXN20 Microcontroller Reference Manual Rev 1 14 14 Freescale Semiconductor...
Page 821: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 Freescale Semiconductor 27 49...
Page 822: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 27 50 Freescale Semiconductor...
Page 1376: ...Memory Map PXN20 Microcontroller Reference Manual Rev 1 A 118 Freescale Semiconductor...