MAC7200 datasheet(314/976 Pages) FREESCALE

314 / 976 page

The SPP DMA Controller Module (SPP_DMA2)

MAC7200 Microcontroller Family Reference Manual, Rev. 2

236

Freescale Semiconductor

12.2.6.3.2

Round Robin Channel Arbitration

Channels are serviced starting with the highest channel number and rotating through to the lowest channel

number without regard to channel priority levels.

All channels are treated equally. Priority levels are not used in round robin mode.

12.2.6.4

DMA Transfer

12.2.6.4.1

Single request

To perform a simply transfer of ’n’ bytes of data with one activation, set the major loop to one (TCD.citer

= TCD.biter = 1). The data transfer will begin after the channel service request is acknowledged and the

channel is selected to execute. Once the transfer is complete, the TCD.done bit will be set and an interrupt

will be generated if properly enabled.

For example, the following TCD entry is configured to transfer 16 bytes of data. The DMA is programmed

for one iteration of the major loop transferring 16 bytes per iteration. The source memory has a byte wide

memory port located at 0x1000. The destination memory has a word wide port located at 0x2000. The

address offsets are programmed in increments to match the size of the transfer; one byte for the source and

four bytes for the destination. The final source and destination addresses are adjusted to return to their

beginning values.

TCD.citer

= TCD.biter = 1

TCD.nbytes

= 16

TCD.saddr

= 0x1000

TCD.soff

= 1

TCD.ssize

= 0

TCD.slast

= -16

TCD.daddr

= 0x2000

TCD.doff

= 4

TCD.dsize

= 2

TCD.dlast_sga

= -16

TCD.int_maj

= 1

TCD.start

= 1 (TCD.word7 should be written last after all other fields have been initialized)

All other TCD fields = 0

This would generate the following sequence of events:

1. IPS write to the TCD.start bit requests channel service,

2. the channel is selected by arbitration for servicing,

3. dma_engine writes: TCD.done = 0, TCD.start = 0, TCD.active = 1,

4. dma_engine reads: channel TCD data from local memory to internal register file,

MAC7200 bảng dữ liệu(PDF) 314 Page - Freescale Semiconductor, Inc

MAC7200 bảng dữ liệu(HTML) 314 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

bảng dữ liệu tải về

Link URL